WO2002054748A1

WO2002054748A1 - System and a method for telephone line sharing

Info

Publication number: WO2002054748A1
Application number: PCT/DK2002/000001
Authority: WO
Inventors: Finn Hovald Ritslev
Original assignee: Rb 2001 Aps
Priority date: 2001-01-02
Filing date: 2002-01-01
Publication date: 2002-07-11
Also published as: DK174465B1; DK200100004A

Abstract

A dual mode telephone system enables a personal computer (16) to remain connected via a premises telephone network (11) and by a dial-up telephone line (1) to a computer network (15), while telephones (4x) connected to the premises network (11) are being used for placing and receiving telephone calls. The system allows any telephone connected to the premises telephone network (11) to be used for traditional and computer network telephone service. Also, telephone and computer network signals may share the same premises telephone network (11) without interfering with each other. Signals representing computer network telephone data are transmitted with priority ahead of signals ahead of signals representing ther data. The invention provides a system and a method.

Description

SYSTEM AND A METHOD FOR TELEPHONE LINE SHARING

Field of the Invention

The present invention relates generally to a system for telephone line sharing. The invention more specifically relates to a system for enhanced, dual mode utilization of a telephone network, by enabling data transmission, while maintaining compatibility with analog telephone equipment. The invention, in another aspect, relates to a method for communication in a telephone network with telephone line sharing.

State of the Art

Many homes are equipped with one or more telephones directly connected to a premises telephone network consisting of telephone wires in a random tree structure, branching to a multitude of wall outlets. Some premises networks include wireless transmission means, e.g. DECT. The great majority of premises telephone networks connect to external phones by means of a single analog telephone access line to a Public Switched Telephone Network (PSTN), and from there to a computer network. With the emergence of computer networks, e.g. the Internet, the sharing between the computer and the telephone of a common access line becomes an issue as the computer blocks the line whenever engaged in a communication to the computer network, preventing traditional telephone usage.

EP 1 052 876 Al discloses a system for time multiplexing blocks of digitized telephony signals simultaneously with transmission of data packets between a transmitter and directly connected receivers, and where the blocks with telephony are transmitted with priority over data packets.

Alternatives are the installation of an additional telephone line, upgrading to ISDN, ADSL, cable TV, or the use of mobile communication. The disadvantages with these solutions are additional installation and subscription costs, sometimes in combination with higher telephone rates for telephone conversations, sometimes requiring a filtering device between each connected telephone and the premises telephone network, sometimes requiring new wiring between the public telephone company's local termination point at the premises - the POTSAP (Plain Old Telephone System Access Point) - and the computer device, or even more expensive, the laying of an entirely new telephone line between the premises and the telephone company's closest central concentration point.

GB 2 350 016 A discloses a system for telephone communication, where a traditional public switched telephone network and a data network shares the subscriber line, e.g. an ADSL connection, and where there is a network interface device at the access point, which electrically separates traditional telephone signals from data signals, and transmits the former over the premises telephone network, and the latter over a dedicated data network. However, telephones connected to the premises network may be used only for traditional telephony.

Most home users and many businesses access the Internet using a modem-equipped computer dialing up, generally using a local telephone number, to a Remote Access Server (RAS), mostly located at a near-by Central Office and connecting to an Internet Service Provider (ISP). The ISP establishes a computer network communication between the Internet and the computer. A temporary IP address is assigned to the computer until the communication between the computer and the Internet is terminated. However, a computer device equipped with V.90 or an older type of modem monopolizes the premises telephone network, thus preventing a telephone connected to the premises telephone network from being used while the computer device is communicating with the computer network.

WO 00/16542 Al shows the sharing of a subscriber line, where a computer device, upon detection of an incoming call, suspends the modem transmission and enables the telephone call. The modem transmission is resumed upon termination of the call.

Some users use computer devices provided with next generation V.92 modem technology. V.92 modems allow reception of incoming telephone calls for a maximum period of up to 16 minutes or even longer, temporarily putting the computer network communication on hold. However, this does not allow the user to initiate telephone calls from telephones directly connected to the premises telephone network, while the computer device is using the same premises network for communicating with the computer network.

The development of the Internet, with its concomitant low communications cost, has spawned its use for computer network telephone service, commonly referred to as "Voice-over-Internet-Protocol" (VoIP). Two methods exist: the (1) device-to-device implementation, and the (2) IP Gateway implementation.

The device-to-device implementations, e.g. PC-to-PC, allow a caller to talk to another party using the same type of device connected to the Internet anywhere in the world for the price of being connected to the Internet, i.e. the price of a local call or less. Several such solutions exist, based e.g. on VoIP telephones with a built-in modem, dedicated devices with a built-in modem to which a telephone may be connected, built-in sound cards of personal computers, or plug-in or external cards with connection to a telephone. However, most such solutions require both users to use the same brand of devices. Furthermore, they prevent the simultaneous use of the premises telephone network by a computer device for communicating with the computer network. Nor do they allow any of the telephones to connect to the premises telephone network for receiving calls or originating calls while the computer device is engaged in a computer network telephone connection.

The IP Gateway implementations allow telephone-to-telephone, telephone-to-PC, and PC-to-telephone connections to any telephone or on-line PC using either the Internet, primarily via central IP Gateways, or, for businesses, an Intranet for speech communications between IP Gateways and routers located in remotely located branch offices.

To initialize an Internet telephone call, a user connects via the Internet with a local IP Gateway. The IP Gateway performs a conversion between traditional telephone service and computer network telephone service. A central IP Gatekeeper is used to provide the caller with the IP address of a remote IP Gateway located within the local telephone region of the party being called. The remote IP Gateway then dials the telephone number of the person who is the target for the call, to allow the two parties to communicate over the Internet. Because both call connections are charged as local, the entire call takes place without long-distance/international charges. Another advantage of the IP Gateway implementation is, that it enables telephone service with the 1+ billion regular and mobile telephones Worldwide.

WO 97/47127 shows the sharing of a dialup subscriber line, where an IP gateway, as part of activation, transmits a command to instruct the public communication network to forward subsequent incoming calls to the IP gateway. Incoming calls are transmitted from the IP gateway as computer network telephone calls to the premises, destined a dedicated telephone and/or a software client in a personal computer connected with an IP modem. Computer device to computer network communication may take place simultaneously with computer network telephone calls. However, telephones connected to the premises network may be used only for traditional telephony.

Various stand-alone devices are available, which enable a regular telephone to be used for computer network telephone service via a computer network. Such devices are connected to the premises telephone network similar to computer devices. However, each device must be connected to a specific telephone, and the device is in general not well suited for receiving calls. Furthermore, such devices prevent the simultaneous use of the premises telephone network by a computer device for communicating with the computer network. Nor do they allow any of the telephones connected to the premises telephone network to receive calls or to place calls while the device is engaged in a computer network telephone connection. Various other devices are available for use together with a personal computer, which enable a regular telephone, directly connected to the device, to be used for computer network telephone service. Some of these devices are integrated inside a computer; others connect to the computer device by a serial bus, yet others by a USB bus. The computer connects to the premises telephone network by means of a modem.

WO 01/22671 Al (Ritslev) provides a system in which any telephone connected to the premises telephone network may use the current the Internet and Intranet telephone infrastructure, without requiring replacement of existing telephones with specially designed devices. However, the use of an Internet browser at the same time as a (computer network) telephone call is using the premises telephone network results in an unacceptable reduction of the quality of service offered to the telephone conversation.

Standard Internet browsers are hampered by inefficiencies in the Internet computer network communication protocols, e.g. HTML/XML. Solutions are available, which offer bandwidth expansion, decreasing the time to download pages by a factor two or more. However, while such solutions may co-exist with the computer networking telephone solutions mentioned above and compensate for the bandwidth lost to telephone service, they still compete for bandwidth with computer network telephone signals, causing an unacceptable reduction the quality of service for the telephone conversation.

On this background, there is a desire for a method and apparatus, which might expand the capacity of the "the last mile" between the subscriber and the public communication networks by providing telephones connected to a premises telephone network connected to the Public Switched Telephone Network (PSTN) by means of a single telephone line, with the service level, stability, and connectivity of the current public switched telephone infrastructure, while allowing the simultaneous use of same premises network for communication between a computer device and a computer network, thereby avoiding the need for wiring of supplemental connections between the telephones; without requiring the user to terminate and subsequently perform time-consuming re-establishment of computer network sessions, whenever a telephone connected to the premises telephone network has been used for making traditional telephone calls; whether computer network telephone service takes place at the same time sharing the same telephone line or not, while offering a high quality of telephone service on "the last mile".

Objects and summary of the invention It is therefore an object of the invention to provide a telephone line sharing system, which provides users connected by means of a single telephone line to a public switched telephone network with the option of keeping a personal computer virtually permanently connected to a computer network, while making and receiving telephone calls at any telephone connected to a premises telephone network shared with the personal computer. Another object is to enable both traditional telephone service and computer network telephone service from any telephone connected directly to the premises telephone network. Yet another object is to improve the quality of service of computer network telephone service on "the last mile" between the subscriber and the public communication networks by serving telephone signals with higher priority than computer device to computer network signals.

According to the invention, in a first aspect, this is achieved by a system as recited in claim 1.

According to the invention, in a second aspect, this is achieved by a system as recited in claim 18.

The response time reduction means of the subscriber system comprises means for the browser data being exchanged between the subscriber and the host system in a compressed format and for decompressing said data before being exchanged with the browser. The response time reduction task may cause a significant load upon the CPU of the computer device involved. The computer device may be off-loaded by further means performing parts of or all of the response time reduction, preferably by firmware executed by a Digital Signal Processor embedded in the subscriber system.

Another object of the present invention is to improve the quality of computer network telephony when the first communications means is simultaneously being used for computer device to computer network communication. Furthermore, and preferably, this is accomplished by the host system comprising further means for receiving incoming communication signals from the public communication network destined the one or more telephones) and/or the at least one computer device and transmitting the computer network telephony signals with priority over the computer device to computer network signals via the public communication network to the subscriber system; and the subscriber system comprising further means for transmitting outgoing computer network telephony signals with priority over computer device to computer network signals via the public communication network to the dual mode host system, which relays said signals to the public communication network.

In most applications the telephones will be connected to one premises telephone network only. However, in some applications there may be two or more different premises telephone networks. Each premises telephone network may connect some or all of the telephones, and the networks may be connected to each other, or they may be totally separated, so that each of them may, independently of the others, establish a connection to the public communication network. The premises telephone network preferably comprises wire connections, such as traditional copper wires, Ethernet cables, optical fiber cables, or any other suitable kind of connections. Typically, premises telephone networks are connected in a random tree structure. Alternatively or additionally it/they may comprise wireless connections, so that the telephones may be e.g. wireless telephones and/or cellular telephones.

Preferably, at least one of the computer devices is a personal computer (PC). However, one or more of the computer devices may alternatively be another kind of computer device, such as a server device, a computer terminal or any other suitable kind of computer device. The dual mode telephone system may comprise several of the above-mentioned kinds of computer devices. In case the dual mode telephone system comprises two or more computer devices, these may be connected via a local computer network, such as a local area network (LAN) or any other suitable kind of local computer network. One or more personal computers may have one or more telephones directly connected. Such telephones may perform computer network telephone service independently of the telephones connected to the premises telephone network. Such connections are treated by the dual mode telephone system as computer device to computer network connections.

Preferably, the host system is a personal computer (PC), a more powerful computer device or two or more computer devices, which may be connected via a local computer network, such as a local area network (LAN) or any other suitable kind of local computer network.

The first communication means preferably comprises suitable wire and/or wireless connections as mentioned above in connection with the premises telephone network. Additionally, it most preferably comprises a POTSAP termination point (Plain Old Telephone System Access Point) for providing access to the public communication network and a connection between the POTSAP and the public communication network, generally an analog telephone line (the PSTN subscriber loop) or a telephone line carrying a traditional analog telephone voice channel, e.g. an xDSL connection. Alternatively, it comprises a mobile telephone for providing access to the public communication network via a public mobile telephone network.

The second communication means may comprise a USB connection, a connection to a COM port, a connection to an Ethernet port, a wireless connection, a connection to a parallel port, and/or any other similar bus connection to a computer device. As mentioned above, the dual mode telephone system according to the invention allows for two or more telephone calls/computer network connections to be performed simultaneously. The term "simultaneously" should be interpreted as follows. At least part of the time a given connection is active, another connection may also be active. That is, the two connections are not necessarily established or terminated at the same time, and the duration of the one connection is not necessarily equal to the duration of the other. Therefore, the fact that one connection is established does not exclude another connection from being established, and hence the person wishing to establish the second connection does not have to wait for the first connection to be terminated.

The public communication network may further comprise a Public Switched Telephone Network, such as the traditional public telephone network; a private telephone network; a PBX (private Branch Exchange); and/or a public mobile telephone network. The public communication network may comprise a global computer network, such as the Internet or the World Wide Web; and/or it may comprise a private computer network, such as an intranet. Furthermore, the public communication network may comprise an IP Gateway connected with a remote telephone network; it may comprise a remote Public Switched Telephone Network local to the recipient of an outgoing call; it may comprise a business' PABX system with embedded IP Gateway functionality connected with a local or corporate private telephone network; it may comprise another remote dual mode telephone system with its premises telephone network; or it may comprise any other suitable kind of communication network.

The splitter device may comprise connection means, such as copper wires, telephone wires, optical fibers, wireless connections and/or any other suitable kind as connection means for establishing direct connections to the public communication network, most preferably via a POTSAP. The splitter device may also comprise control means for controlling the communication between the telephone/computer and the public communication network, and the control means may comprise relays or similar switching circuits.

The modem device may also comprise connection means like the ones mentioned above for establishing direct connections between the various devices supported by the modem device. In the preferred embodiment, the modem device may comprise computing means enabling it to perform a conversion of traditional telephone signals to computer network signals, including making phones ring, detecting off/on-hook state, generating pending tone, detecting dual-tone multi-frequency (DTMF), suppressing noise and generating white noise, substituting lost and timed-out speech packets, generating busy tone, speech digitization and compression, and echo cancellation. In an alternative embodiment, the conversion functions are split between the modem device and one or more of the computer devices, preferably with the computer device handling speech compression, e.g. in accordance with the international standard G.711, G.723a and/or G.729.1 protocols. This way a traditional telephone call may be converted into a computer network telephone call, whereby the call may be exchanged via the public communication network simultaneously with computer device to computer network communication.

Alternatively, the conversion may be partly performed by the modem/splitter device, preferably phone ringing, substitution of lost or timed-out speech packets, speech digitization and echo cancellation, while the remaining may be performed in one of the computer devices, e.g. speech compression and VoIP call management.

The splitter device preferably comprises means for changing the frequency of a first communication signal being exchanged with the modem device on the premises telephone network so as to avoid interference between said communication signal and telephone signals being exchanged with telephones on the same premises telephone network. Furthermore, a second communication signal may to be transmitted simultaneously with the first communication signals and any control signals between the splitter device and the modem device. The second communication signal is preferably transmitted on the same premises telephone network in same the frequency band as the one used for the first communication signal with a computer network protocol ensuring one not interfering with the other.

The first communication signal may be computer network telephone signals and the second communication signal may be computer network signals. The computer network telephone service is exchanged via a computer network with an IP Gateway, which handles the conversion from computer network telephone service to traditional telephone service and manages a "local" remote telephone connection. Thus, the dual mode telephone system is able to "bypass" the traditional telephone connection, so that a call may be established even though another connection is already active. This allows the simultaneous transmission of two or more telephone calls and computer network connections between two or more telephones, a computer device, and the public communication network.

The dual mode telephone system may comprise at least two telephones connected via the premises telephone network. In this case each telephone is capable of performing traditional telephone service as well as computer network telephone service independently of the other telephones. In this embodiment any of the telephones connected via one of the premises telephone networks may be used for establishing a connection to the public communication network. There is thus not just one dedicated telephone, which may be used for such a purpose. However, at any given point in time, only speech from one telephone connection is transmitted as any other telephone connection with another telephone on the same premises telephone network must be put on hold.

Alternatively, another modification technology than a frequency shift may be applied, provided the technology ensures that the signals between the first and the modem device do not interfere with analog telephone signals conveyed on the same premises telephone network. Yet another alternative to modifying the signals is to provide a dedicated connection for transmitting signals between the first and the modem device.

During off-line mode of operation, power to the dual mode telephone system and to the premises telephone network is drawn from the Public Switched Telephone Network. During on-line mode of operation, for safety reasons, power to the premises network, e.g. to make connected telephones ring, is not drawn from the public switched network but is provided from the dual mode telephone system. Power may be supplied at the termination point POTSAP, e.g. from a regular power outlet at that position, however this adds to the cost and to the complexity of the installation, in particular if a suitable outlet is not readily available. Therefore it is preferred to supply the power via the modem device, drawing the power from the modem power supply, which is generally installed anyway. The power supply of the modem device may comprise a power outlet, wiring, one or more adapters, one or more transformers or any other suitable means for distributing/supplying power to various parts of the dual mode telephone system.

The power supply means of the modem device may supply power to all of the dual mode telephone system, or it may only supply power to a part of the dual mode telephone system, such as just the communication device, only one of the communication devices, at least one premises telephone network, only the part comprising the communication means or any other suitable part of the system.

The dual mode telephone system may allow at least one premises telephone networks to be switched between a Public Switched Telephone Network (PSTN) and the dual mode telephone system, so as to allow in the passive mode only traditional telephone service, and in the active mode enhanced service, e.g. two or more telephone calls/computer network simultaneous connections, while still maintaining the service level, stability and connectivity of traditional telephone calls and computer network connections. A computer device of the dual mode telephone system may control the mode switching.

It is thus possible to use the premises telephone network in a traditional way, i.e. for performing traditional telephone calls, one at a time (the passive mode). On the other hand it is also possible to enter a mode (the active mode), which allows for two or more simultaneous connections. Therefore, the dual mode telephone system according to the invention is fully compatible with existing premises telephone networks.

The splitter device includes means to ensure that the premises telephone network defaults to the passive mode, whenever a part of the dual mode telephone system is un-powered.

In other embodiments, one or more of the parts of the dual mode telephone system described above may be embedded in a computer device. The computer device may be one of the communication devices of the system, or it may be an external computer device. Alternatively, parts of the dual mode telephone system may be integrated with a computer device, e.g. in form of a printed circuit board, in which case an internal bus of the computer device, e.g. PCI or PMCIA, is included in the second communication means, or the dual mode telephone system may be a totally integrated part of a computer device.

The invention, in a third aspect, provides a method as recited in claim 19.

The invention, in a fourth aspect, provides a method as recited in claim 34.

According to these methods, it is possible to establish a second connection even though a connection is already being performed, and it is possible to transmit the communication signals of the two connections simultaneously. One of the connections may be a computer network telephone connection. Thus, it is possible to establish a telephone call while a computer connection is being performed, and vice versa.

The computer network telephone signal may be a signal according to the Voice-over-Internet-Protocol (VoIP) and computer device to computer network according to the TCP/IP protocol.

Advantageous embodiments appear from the dependent claims.

These and other objects, features, advantages and alternative aspects of the present invention will become apparent to those skilled in the art from consideration of the following detailed description taken in combination with the accompanying drawings.

Brief description of the drawings In the following detailed description, reference will be made to the attached drawings in which:

Figure 1 is a schematic diagram illustrating an overview of the overall network of the present invention in the preferred embodiment. Figure 2 is a schematic diagram illustrating in more details the preferred embodiment.

Figure 3 is a block diagram illustrating yet further details and their interconnections.

Figure 4 is a block diagram illustrating routing of traditional telephone calls during off-line mode of operation.

Figure 5 is a block diagram illustrating routing of computer device to computer network communication during on-line mode of operation.

Figure 6 is a block diagram illustrating routing of an incoming traditional telephone call during on-line mode of operation.

Figure 7 is a block diagram illustrating routing of an ingoing/outgoing computer network telephone call during on-line mode of operation in an embodiment, in which a computer device is performing part or all of the speech conversion.

Figure 8 is a block diagram illustrating routing of an ingoing/outgoing computer network telephone call during on-line mode of operation of a variant embodiment, in which a computer device is performing part or all of the speech conversion.

Figure 9 is a schematic diagram illustrating an overview of the overall network of the present invention in a variant embodiment, which does not include bandwidth expansion.

Figure 10 is a block diagram illustrating routing of computer device to computer network communication of the Fig. 9 embodiment.

Figure 11 is a schematic diagram illustrating a variant embodiment of the invention.

Figure 12 illustrates a variant embodiment with directly connected telephones. Figure 13 is a schematic diagram illustrating a stand-alone embodiment of the invention.

Figure 14 is a block diagram illustrating routing of bandwidth expanded computer device to computer network communication of the Fig. 13 embodiment.

Figure 15 is a block diagram illustrating a variant embodiment with a further secondary telephone network interconnecting modem device and splitter device. Figure 16 is a schematic diagram illustrating another stand-alone embodiment of the invention with the modem functionality embedded in the computer device.

The numbering scheme applied adheres to the following conventions: 1-9 Physical connection; 91, 92, ... 99 Connection used for exchange of signals . Computer network communication signals comprise the exchange of signals for computer device to computer network communication and signals for computer network telephone service.

The subsequent section describes the preferred embodiment of the dual mode telephone system. Furthermore, a few additional embodiments have been included expanding upon the preferred embodiment to illustrate other important aspects of the current invention. However, these embodiments are provided as examples, and do not limit the scope of other embodiments foreseen within the scope of this invention.

Detailed description of the preferred embodiments

A wide range of embodiments of the dual mode telephone system are foreseen, some examples being:

• Embodiments comprising bandwidth expansion and those without;

• Embodiments comprising telephones directly connected to the subscriber system and those without;

• Embodiments, which enable any regular telephone connected to a premises telephone network to be used at the same time as computer device to computer network communication on the same premises network, and stand-alone embodiments where only telephones directly connected to the system may be used; • Embodiments sharing the premises telephone network between regular telephone and computer network communication, and those which do not by relying instead on further interconnection means dedicated the later type of communication;

• Embodiments where the computer device does not participate in conversion of traditional telephone calls to computer network telephone calls and those where it does; • Embodiments comprising embedded modem facilities for converting digital signals to the analog format supported by the public communication network and those, which depend upon the computer device for this;

• Embodiments using embedded V.92 modem means or similar for handling incoming regular telephone calls and those which do not; • Embodiments dependent upon the methods of transferring incoming traditional telephone calls away from a telephone line engaged in computer device to computer network communication to an IP Gateway for converting the telephone call to a computer network telephone service call and those, which do not. Fig. 1 depicts the overall network and the integration of the preferred embodiment of the dual mode telephone system with telephones 41, 42, 43, ...4x directly connected to a premises telephone network 11, a public communication network 15, and a computer device 16.

The public communication network 15 (Fig. 2) comprises a Public Switched Telephone Network 14 including the public telephone company's termination point POTSAP 13, a computer network 18 connected to the Public Switched Telephone Network 14, a Remote Access Server 81, an IP Gateway 82, and a remote public switched telephone network 17.

In the preferred embodiment of the present invention illustrated in Fig. 1, 2, and 3, the dual mode telephone system comprises a host system 83 and a subscriber system 12, the subscriber system 12 consisting of two devices, a modem device 32 and a splitter device 31. Modem device 32 includes power supply (not shown), second and fifth receiving means, while the splitter device 31 includes first and fourth receiving means and the host system 83 includes third receiving means.

The first receiving means receives power for the splitter device 31 from and exchanges analog signals with a Public Switched Telephone Network 14; the second receiving means exchanges digitized and control signals with computer device 16; the third receiving means exchanges digitized signals with computer network 18; the fourth receiving means exchanges modified analog telephone signals, modified computer network communication signals, and control signals with, and supplies during offline operation electrical power to the premises telephone network 11. The modified computer network communication signals and control signals are exchanged at another frequency than that used for analog telephone signals; and the fifth receiving means exchanges modified analog telephone signals, modified computer network communication signals, and control signals with, and supplies during on- line operation electrical power to the premises telephone network 11. The modified computer network communication and control signals are exchanged at another frequency than that used for analog telephone signals.

In a "no bandwidth expansion" embodiment of the present invention illustrated in Fig. 9 and 10, which does not include means for bandwidth expansion, the dual mode telephone system comprises two devices, a modem device 32 and a splitter device 31. Modem device 32 includes power supply (not shown), second and fifth receiving means, while the splitter device 31 includes first and fourth receiving means. The first receiving means, the second receiving means, the fourth receiving means and the fifth receiving means are as previously described. In a "directly connected phones" embodiment of the present invention illustrated in Fig. 12, the dual mode telephone system comprises a host system 83 and a subscriber system 12 consisting of two devices, a modem device 32 and a splitter device 31. Modem device 32 includes power supply (not shown), second, fifth, and ninth receiving means, while the splitter device 31 includes first and fourth receiving means and the host system 83 contains third receiving means.

The first receiving means, the second receiving means, the third receiving means, the fourth receiving means, and the fifth receiving means are as previously described. The ninth receiving means exchanges analog telephone signals with telephones 51,...5x connected directly to modem device 32.

In a "stand-alone" embodiment of the present invention illustrated in Fig. 13, the dual mode telephone system comprises a host system 83 and a subscriber system 12 consisting of modem device 32. Modem device 32 includes power supply (not shown), second and fifth receiving means, while the host system 83 includes third receiving means. The first receiving means, the second receiving means, the third receiving means and the fifth receiving means are as previously described.

In a "dedicated interconnection" embodiment of the present invention illustrated in Fig. 15, the dual mode telephone system comprises a host system 83 and a subscriber system 12 consisting of two devices, a modem device 32 and a splitter device 31. Modem device 32 includes power supply (not shown), second, fifth, and seventh receiving means, while the splitter device 31 includes first, fourth and eighth receiving means and the host system 83 includes third receiving means.

The first receiving means, the second receiving means, and the third receiving means are as previously described. The fourth receiving means exchanges analog telephone signals with, and supplies during off-line operation electrical power to the premises telephone network 11. The fifth receiving means exchanges analog telephone signals with, and supplies during on-line operation electrical power to the premises telephone network 11. The seventh receiving means exchanges computer network communication and control signals with the secondary premises telephone network 19. The eighth receiving means exchanges computer network communication and control signals with the secondary premises telephone network 19.

One or more regular telephones 41, 42, 43,...4x are connected to a premises telephone network 11, which comprises telephone wires in a random tree structure 60 to premises telephone wall outlets 61, 62, 63,...6x. The premises telephone network 11 would, prior to the installation of the subscriber system 12, generally have been directly connected to the public telephone company's termination point POTSAP 13 by connection 4. Connection 16 between the public telephone company's termination point POTSAP 13 and the Public Switched Telephone Network 14 is an analog telephone line or alternatively, a telephone line carrying a traditional analog telephone voice channel, e.g. an xDSL connection.

Connection 9 (alternative embodiment illustrated in Fig. 12) may comprise a telephone wire terminated in a regular telephone outlet. The computer device 16 includes a micro-controller (not shown) and memory (not shown). The computer device 16 may be a personal computer.

Host system 83 is connected to the public communication network 15 by connection 3. This can be accomplished in the same means as computer systems may interface with a computer network for high-speed transmission of data, e.g. ISDN-2, ISDN-30, Tl, and/or El connections. Host system 83 may be one or more personal computers and/or more powerful computer systems.

Most embodiments of the dual mode telephone system comprise a subscriber system 12 consisting of a modem device 32 and a splitter device 31. The modem device 32 and the splitter device 31 are interconnected by means of the premises telephone network 11. Embodiments including bandwidth expansion further include host system 83 (e.g. Fig. 1, 2, and 3). Embodiments, which do not support simultaneous speech and computer network communication on the premises telephone network 11, comprise modem device 32 and host system 83 (e.g. Fig. 13, 14 and 16). Modem device 32 is integrated into the overall network by connecting it to the premises telephone network 11 and the computer device 16.

Modem device 32 is connected by means of connection 5 to the premises telephone network 11 at a regular telephone wall outlet (not numbered). This can be accomplished by connecting regular telephone wiring between the wall outlet (not numbered) and the modem device 32. Additionally, in another embodiment illustrated in Fig. 15, modem device 32 can be connected to the splitter device 31 by means of/to a secondary premises telephone network 19, e.g. a dedicated wire, an Ethernet cable, a radio transmission or similar wireless communication; the secondary premises network 19 intended for control signals, computer network telephone service, and computer device to computer network signals, thus avoiding the need for the modification of said signals used in the preferred embodiment of the invention.

Modem device 32 is further connected by connection 2 to the computer device 16. Connection 2 is preferably by means of a connection to the computer device 16's universal serial bus (USB) port (not shown). This can be accomplished by inserting a USB cable between the modem device 32 and the computer's USB port. One or more USB ports are standard in new computer devices, and can be added to an existing system by an ordinarily skilled artisan. These are examples of course, not limiting how any connection known to an ordinarily skilled artisan could be used to connect the computer device 16 and modem device 32. Alternatives to connection 2 are to use a connection to the serial port of the computer device 16; to use a connection to an Ethernet port on the computer device 16; to integrate parts of or all of the subscriber system 12 with the computer device 16, e.g. in form of a printed circuit board, in which case an internal bus of the computer device, e.g. PCI or PMCIA, constitutes the connection 2; or as yet another alternative totally integrate parts or all of the subscriber system 12 in the computer device 16, eventually in form of an ASIC chip or a similar technology.

Splitter device 31 is integrated into the overall network by connecting it to a Public Switched Telephone Network 14 and to the premises telephone network 11. Splitter device 31 is connected by connection 4 to the premises telephone network 11. This can be accomplished in the same way as the premises telephone network 11 is connected with the public telephone company's termination point POTSAP 13. Additionally, in another embodiment illustrated in Fig. 15, splitter device 31 can be further connected to the modem device 32 by means of/to a secondary telephone network 19 as already described. Splitter device 31 is further connected by connection 6 to the public telephone company's termination point POTSAP 13, which by means of connection 1 is connected to the Public Switched Telephone Network 14. Connection 6 can be accomplished by connecting regular telephone wiring between the splitter device 3 land the public telephone company's termination point POTSAP 13.

Modem device 32, in the preferred embodiment (Fig. 3), comprises power circuit 32P, control circuit 33B, modem modification circuit 34M, compression circuit 35, conversion circuit 37, PABX-emulator circuit 37A; modem circuit 38, expansion circuit 36, and driver circuit 39; while splitter device 31 comprises power circuit 3 IP, control circuit 33, splitter modification circuit 34S, and splitter PABX- emulator circuit 37S. Fig. 8 illustrates a "computer device participating in VoIP conversion" alternative embodiment. Fig. 10 illustrates a "no bandwidth expansion" alternative embodiment. Fig. 14 illustrates a "stand-alone" alternative embodiment.

In a well-designed embodiment of the invention, splitter device 31 draws a minimum of power, enabling the Public Switched Telephone Network 14 to supply the power similar to how traditional telephones are powered. Power circuit 3 IP supplies power solely to splitter device 31's circuit. Furthermore, power is supplied to modem device 32 by connecting said device's power circuit 32P to a power supply wall outlet using an ordinary power cable similarly to how a computer device is connected to a power supply wall outlet. Power circuit 32P supplies power to modem device 32's circuit and, during on-line mode of operation, to the premises telephone network 11.

In alternative embodiments of the invention, power is supplied to the splitter device 31 and to the modem device 32 by separate cable connections to power wall outlets. Furthermore, in yet other alternatives, one may use the premises telephone network 11 to supply power from either modem device 32 to splitter device 31 or vice versa, if only one is provided with power. In still other embodiments of the invention, the USB port not only allows data communication between modem device 32 and the computer device 16, but also provides power to the modem device 32's internal components, and during on-line operation to the premises telephone network 11. However, great skill must be exercised in order to use the USB for supplying sufficient power to make the telephones 41, 42, 43, ...4x ring appropriately. Whichever the case, great care should be given in the design to ensure appropriate measures are taken to comply with electrical safety regulations, specifically regarding any isolation of components supplied with power from a normal power wall outlet from those components, which are supplied from the public communication network 15.

Control circuit 33 connects to first and fourth receiving means. It comprises means, e.g. a relay or a similar mechanism, for switching between a direct electrical connection between first and fourth receiving means, and a connection between first receiving means and splitter modification circuit 34S.

Modem modification circuit 34M connects via fifth and splitter modification circuit 34S via fourth receiving means with the premises telephone network 11. Their function is described under operation of the system. In an alternative embodiment illustrated in Fig. 15, the modification of signals between control circuit 33 and splitter modification circuit 34S may be replaced by a dedicated connection 19 avoiding the need for sharing the premises telephone network 11 for simultaneous telephone service and computer network communication and the resulting associated need for modification circuit. This connection may be a traditional copper wiring, Ethernet cables, an optical fiber cable, a wireless connection, or any other suitable kind of connection.

Modem PBX-emulator circuit 37E connects via fifth receiving means to the premises telephone network 11. It provides an electrical interface between telephones of the premises telephone network 11 and conversion circuit 37 and control circuit 33B. It performs together with conversion circuit 37 the functions equivalent to those of a conventional telephone switch's line card to a telephone. It comprises means for detecting off/on-hook telephone signaling and for generating ringing signals. Splitter PBX-emulator circuit 37S connects via first receiving means to the public communication network 15. It comprises means for detecting an incoming ring signal, "hang-up" signaling from the public communication network 15, and, optionally, means for generating and transmitting DTMF- signals to the public communication network 15. The splitter PBX-emulator circuit 37S is optional and required for embodiments supporting V.92 and/or controlling call forwarding to IP gateway 82.

Regular telephone signals 91 are converted to Voice-over-IP signals 97 either, as in the preferred embodiment (Fig. 7), by IP Gateway functionality entirely embedded in conversion circuit 37 and compression circuit 35 or, as in an alternative embodiment (Fig. 8), partly by conversion circuit 37 comprised in modem device 31 and the remaining by compression software 25 comprised in computer device 16. Conversion circuit 37 and/or compression circuit 35 comprises micro-controller, digital signal processor and memory, in the preferred embodiment shared with other circuits. The IP Gateway functionality is based upon the H.323, and/or SIP protocol, and/or a similar international standard. Speech compression is preferably based upon the G.711, G.723a, or G.729 protocol. Whichever the case, it must be emphasized, that the embedded IP Gateway functionality implemented must be fully compatible with that of the IP Gateway 82.

Conversion circuit 37 converts analog speech signals 91 received from the premises telephone network 11 into digitized speech signals 97 and performs preferably echo cancellation and other speech quality improving technologies; and converts digitized signals vice versa into speech signals for retransmission to the premises telephone network 11.

Compression circuit 35 comprises means for speech compression and computer network telephone connection management including TCP/IP enveloping. In an alternative embodiment (Fig. 8), these fimctions are implemented by compression software 25 embedded in computer device 16. The advantage of embodiments using a computer device for performing part of the VoIP conversion over the preferred embodiment is that far more components are readily available, specifically software. In alternative embodiments, other splits of IP Gateway functionality between the modem device 32 and the computer device 16 may be applied, provided they combined include all required functionality. However, a drawback is that such embodiments require the computer device to be powered up and online in order to enable computer network telephone service.

Modem circuit 38 comprises means for converting digital signals to analog signals in a format compliant with the protocol used for exchange of data between a computer device and a Public Switched Telephone Network and vice versa. Modem circuit 38 may comprise micro-controller, digital signal processor or may be embedded in similar means in other circuit of the modem device 32. The modem circuit 38 includes, in the preferred embodiment, V.92 modem functionality. In an alternative "single device" embodiment (Fig. 16), which comprises bandwidth expansion and computer network telephone service only from a directly connected telephone 5x, the modem circuit 38 is replaced by means 38X in the computer device 16 performing this functionality.

In embodiments without bandwidth expansion (Fig. 10), standard browser software 21 interfaces via the computer device's standard TCP/IP stack (not shown) and the device driver 29 with the modem functionality of the subscriber system 12.

In embodiments like the preferred one (Fig. 3), expansion software 23 intercepts, as described below, all signals between standard browser software 21, e.g. Microsoft's Explorer and/or Outlook and/or other e-mail programs and/or similar client software, and the computer device's standard TCP/IP stack (not shown) and exchanges said intercepted signals with the host system 83 via the public communication network 15. Expansion circuit 36 solely exchanges signals with expansion software 23 via driver circuit 39 and driver software 29. Expansion circuit 36 may comprise digital signal processor and/or micro-controller and/or memory, some or all of which may be shared with other dual mode telephone circuit. Expansion circuit 36 may, in alternative embodiments, not be present, in which case its functions are performed by expansion software 23. Driver circuit 39 connects to second receiving means.

Control signals for variants of the subscriber system 12, which are controlled from the computer device 16, are received from said device via connection 2. Control signals in variants of the subscriber system 12, which are capable of stand-alone operation without the computer device 16 being active, are controlled by means comprised in compression circuit 37.

Having described in detail the overall network, a detailed operational description of the dual mode telephone system will now be provided. It presents, amongst other, how signals are exchanged, generally from the call originating telephone to the answering telephone; similarly from computer device to computer network. Connections are full-duplex bi-directional with signals passed in the opposite direction being handled similarly but in the reverse order. Signals transmitted from the public communication network to the dual mode telephone system are termed incoming signals, while those in the opposite direction to are termed outgoing.

The system has two modes of operation, off-line and on-line. Off-line mode may also be referred to as passive mode, default mode, or direct mode. On-line mode may also be referred to as active mode, line sharing mode, premises network sharing mode, or enhanced mode. Off-line Mode of Operation.

During off-line mode of operation, the premises telephone network 11 is electrically connected directly to the Public Switched Telephone Network 14 as illustrated in Fig. 4. In this state, power to the premises telephone network 11 is provided from the Public Switched Telephone Network 14. Thus, all telephones 41, 42, 43,...4x operate traditionally, i.e. as before the subscriber system was installed.

Going from on-line to off-line operation

The actions required in going from on-line operation (Fig. 5 and/or 6 and/or 7) to off-line operation (Fig. 4) comprises most importantly the steps of

• Isolating the premises telephone network 11 from modem PBX-emulator circuit 37E by disconnecting the two electrically, e.g. by a relay or a similar means (not shown). This step is first for electrical safety reasons;

• Establishing an electrical connection between the premises telephone network 11 and the Public Telephone Switched Network 14, e. g. by a relay or similar mechanism in control circuit 33 enabling power and telephone signals to pass freely between said two networks; • Transmitting an instruction to the public communication network 15, by means of appropriate DTMF signals transmitted by splitter PABX-emulator circuit 37S, telling the public communication network 15 to clear any call-forwarding instructions and thus to transmit henceforth any incoming telephone calls to the access point 13 as traditional phone calls. The appropriate DTMF signals depend upon the public communication network operator.

The off-line mode of operation should be the start-up mode of operation of the system, and also the default mode to which the system automatically falls back, should power disappear from the subscriber system 12 or should another serious error occur to said system. This is secured by including in the splitter a logic for deciding the mode of operation and means for transmitting, upon switching to default mode, an appropriate DTMF tone signal instruction to the access point 13, which is connected to the public communication network 15. The logic will continually monitor the premises network supply voltage as well as the presence of a "keep alive" signal from the modem device 32. For safety reasons, both of these must vanish before the logic decides to declare a switch to default mode.

On-line Mode of Operation Fig. 5, 6 and 7 illustrate routing of a specific type of connection during on-line mode of operation of the preferred embodiment. While not illustrated specifically, connections may be simultaneous, e.g. computer device to computer network simultaneously with computer network telephone service illustrated by Fig. 5 overlapping Fig. 7. Fig. 8 illustrates computer network telephone service in an 5 embodiment with the computer doing part of the VoIP conversion. Fig. 10 illustrates computer device to computer network communication in an embodiment without bandwidth expansion. Many other combinations are possible, but are not illustrated nor described explicitly.

Going from off-line to on-line 10

Going from off-line to on-line comprises the steps of

• Establishing a connection between modem modification circuit 34M and splitter modification circuit 34S, intended for simultaneous exchange of control signals 99, modified signals for computer device and computer network communication 95, modified signals for computer network telephone

15 communication 95, and incoming speech signals 92;

• Issuing a control signal 99 from/via modem device 32 to splitter device 31 to tell the splitter device 31 that the modem device 32 wishes to switch to active mode. The splitter device 31 responds by isolating the premises telephone network 11 from the access point 13, i.e. from the Public Telephone Switched Network 14, e.g. by disconnecting the two electrically by a relay or a similar

20 means (control circuit 33) and by issuing to the access point 13, i.e. to the public communication network 15, a call-forwarding instruction, by means of appropriate DTMF signals transmitted by splitter PABX-emulator circuit 37S, telling the public communication network 15 to henceforth forward any incoming calls to an IP Gateway 82 for conversion to computer network telephone service 98 to be destined to the IP-address assigned to the premises computer network termination 13.

25 The appropriate DTMF signals depend upon the public communication network operator. The splitter device 31 may transmit a confirmation signal along the premises telephone network 11 to the modem device 32;

• Providing power to the premises telephone network 11 from modem PBX-emulator circuit 37E.

30 The exchange of signals between the modem modification circuit 34M and the splitter modification circuit 34S is performed by modem modification circuit 34M applying a frequency shift on received signals before these are relayed (34M -> 34S) to the splitter modification circuit 34S to frequency bands spaced from those used for traditional voice telephone service such that this communication (95/92/99) will not interfere with a simultaneous transmission of traditional analog telephone signals

35 91 on the premises telephone network 11 to the telephones 41, 42, 43,...4x; and by splitter modification circuit 34S modifying back the relayed modified signals to the originally received format before these regenerated signals are retransmitted to the access point 13; and vice-versa for signals received by splitter modification circuit 34S from the access point 13, and which are forwarded in modified format along the premises telephone network 11 to the modem modification circuit 34M, regenerated and, in case of computer network telephone signals, converted and retransmitted as traditional analog telephone signals from the modem device 32 back along the premises telephone network 11. The exchange of all of these signals may take place simultaneously and without interfering with one another. In this way, the telephone signals will generally travel twice along the premises telephone network 11, one pass being in a modified format and the other pass being in a traditional analog telephone format 91.

As the frequency range of normal telephone signals is generally limited to below 3 kHz, and as the premises telephone network 11 will generally easily carry signals at frequencies ranging to 100 kHz or 1 MHz, there is plenty of spare capacity in the premises telephone network 11 by using higher frequencies. A favored embodiment reformats the signals by simply shifting the frequency range upwards by 100 kHz. This method allows a simple implementation of the circuit in the splitter, with a low power consumption, and avoids interference with other electrical installations, such as the telephones 41, 42, 43,...4x.

An alternative modification scheme to the frequency shift technology suggested may be used, e.g. another form of frequency shift, sideband, wireless, xDSL, homePNA, or equivalent, provided the resulting signals do not interfere with each other and permit a simultaneous transmission of analog telephone signals on the premises telephone network 11 to the telephones 41, 42, 43, ...4x.

Exchanging computer network and computer network telephone signals between modem circuit 38 and the Public Switched Telephone Network 14 further comprises the steps of

• Modem circuit 38 converting outgoing signals received from driver circuit 39 (96) and/or compression circuit 35 (97) to a format compliant with the protocol used for digital exchange via a Public Switched Telephone Network with a computer network, subsequently transmitting said converted signals via modem modification circuit 34M and 34S as previously described; • Splitter modification circuit 34S hence re-transmitting the regenerated converted signals (94/98) to the Public Switched Telephone Network 14;

• And vice versa for incoming signals (94/98) received by splitter modification circuit 34S from the Public Switched Telephone Network 14, simultaneously and independent of the outgoing signals; i.e. communication is full-duplex bi-directional. In embodiments including a host system 83 with bandwidth expansion, as do the preferred embodiment (Fig. 5), exchanging computer device to computer network signals between client software 21 and the computer network 18 further comprises the steps of

• Establishing a connection (96/97-95-94/98) between expansion software 23 and expansion server 83 via the public communication network 15 as described below;

• Expansion software 23, expansion circuit 36 and host system 83 jointly reducing the amount of data exchanged between browser software 21 and the computer network 18 "on the last mile". Expansion circuit 36 comprises together with expansion software 23 means for improving the efficiency of computer device to computer network communication by intercepting said signals from computer network client software 21 intended for computer network communication by exchanging these via the host system 83 such that the amount of computer network data flowing between the computer device 16 and the host system 83 is reduced, e.g. by means of data compression technologies and/or by avoiding repetition of page downloads and/or by memory/disk caching; all techniques known to artisans skilled in Internet browser data handling. Expansion circuit 36 reduces the expansion software 23's utilization of the computer device 16's CPU, e.g. by implementing parts of data compression algorithms in a high performance digital signal processor;

• Incoming computer network telephone signals 98 from an IP Gateway 82 are forwarded to host system 83, which relays said signals to the subscriber system 32, whether from in- or outgoing calls. Host system 83 forwards to the computer device 16 computer device to computer network signals 94 and computer network telephone signals 98, the computer network telephone signals being forwarded with priority ahead of other data signals;

Outgoing computer network telephone signals 98 are forwarded via the public communication network 15 to host system 83, which relays said signals to the IP Gateway 82 for further processing, whether from in- or outgoing calls.

Modem circuit 38 and/or driver circuit 39 and/or driver software 29 comprises further means for serving computer network telephone signals 97 with priority over computer device to computer network signals 96 so as to always allocate the former a maximum amount of bandwidth, e.g. by throttling computer device to computer network signals whenever competing for bandwidth with computer network telephone signals, thus providing computer network telephone signals an improved quality of service.

Dual mode telephone system performing VoIP conversion (Fig. 7)

Going from off-line to on-line mode of operation initiated by a compression circuit 35 further includes establishing a computer network communication session (96-95-94 in Fig. 7) between the subscriber system 12 and the computer network 18, e.g. by initiating an Internet session with an Internet Service Provider (ISP). This takes place by the compression circuit 35 exchanging computer network "initialization" signals via modem circuit 38 with the computer network 18 as previously described.

A parallel and simultaneous computer network connection (96-95-94 in Fig. 5 or Fig. 10) between computer device 16 and computer network 18 may be established and terminated at any point in time while the above mentioned session is active. Such connections are established by the computer device 16 exchanging computer network signals via the driver circuit 39, modem circuit 38, modem modification circuit 34M and 37S with the Public Switched Telephone Network 14 and vice versa as described above.

Incoming Computer Network Call (Fig. 7)

An incoming computer network call from a telephone 7y comprises the steps of • Splitter modification circuit 34S receiving a "call imtialization" computer network telephone signal 98 originating from IP Gateway 82 and forwarding said signal to the compression circuit 35 as previously described;

• Compression circuit 35, recognizing the "call initialization" signal 97, and subsequently making the PABX-emulator circuit 37A generate a ringing signal to the premises telephone network 11; • The compression circuit 35 awaiting a "hang-up" computer network telephone signal or any similar signal originated from IP Gateway 82 now or at any later point in time during the call, and responding by terminating the call and re-establishing the state of the dual mode telephone system to the one ruling prior to the call;

• PABX-emulator circuit 37A detecting a hand-set off-hook signal from one 4x of the telephones 41, 42, 43, 44, ...4x, and responding by causing compression circuit 35 to forward a "connection established" computer network telephone signal to IP Gateway 82 as previously described;

• Subsequently and until the call is terminated the further steps of

• Conversion circuit 37 converting received analog speech signals 91 via the premises telephone network 11 into digitized speech signals and transmitting said signals to compression circuit 35; • Compression circuit 35 further transforming the converted signals to computer network telephone signals 97, which are transmitted to IP Gateway 82 as previously described;

• IP Gateway 82 converting the received computer network telephone signals 98 to traditional telephone signals to be transmitted to telephone 7x;

• And vice versa for incoming computer network telephone signals 98 originating from telephone 7x to telephone 4x simultaneously and independent of the outgoing signals; i.e. the communication is full-duplex bi-directional. Outgoing Call (Fig. 7)

An outgoing call/connection in form of a computer network telephone session from any one 4x of the telephones 41 , 42, 43, ...4x comprises the steps of

• Off-hook of the handset of any one 4x of the telephones 41, 42, 43, 44, ...4x initiates an outgoing computer network telephone call/connection;

• Conversion circuit 37 generates a dial tone signal to the premises telephone network 11 ;

• The conversion circuit detects each number entered by the telephone's keypad and transmitted as a dual-tone multi-frequency (DTMF) tone signal 91 via the premises telephone network 11 ;

• The conversion circuit 37 converts each received DTMF tone signal to a digitized number signal, which is transmitted to the compression circuit 35;

• Compression circuit 35 composes a "telephone number" computer network telephone signal which is forwarded (97-95-98) to the IP Gateway 82 as previously described; • Any subsequent "destination busy" computer network signal (98-95-97) received by the compression circuit 35 from IP Gateway 82 as previously described makes the conversion circuit 37 generate a busy tone signal 91 to the premises telephone network 11;

• Subsequently and until the call is terminated steps identical to the speech handling for incoming computer network calls. • On-hook of the handset 4x now or at any later point in time during the call causes the compression circuit 35 to terminate the connection (97-95-98) by forwarding a "call complete" signal to the IP Gateway 82 as previously described, whereby the state of the dual mode telephone system is reestablished to the one ruling prior to the call.

Computer device performing part of VoIP conversion (Fig. 8)

Going from off-line to on-line mode of operation is initiated by a computer device 16 and includes establishing a computer network communication session (97-95-98 in Fig. 8) between the computer device 16 and the computer network 18 via the Public Switched Telephone Network 14, e.g. by initiating an Internet session with an Internet Provider (ISP). Computer device 16 exchanges computer network "initialization" signals via driver circuit 39 with modem circuit 38 for exchange with the computer network 18 as previously described.

The handling of calls is similar to calls where the computer device 16 is not involved as previously described in (a) above other than • Functions performed by compression circuit 35 are instead performed by IP Gateway compression software 25 comprised in the computer device 16. The computer device 16 should preferably be a personal computer;

• Signals exchanged between conversion circuit 37 and compression circuit 35 are replaced by signals exchanged via driver circuit 39 and driver software 29 comprised in the computer device 16 with the compression software 25. The driver software 29 should preferable emulate a sound card driver, as client software for implementing compression is readily available from the owner of the IP Gateway 82, generally for free;

• Signals exchanged between modem device 38 and compression circuit 35 are instead exchanged with the computer device 16.

Incoming Public Switched Network Call (Traditional Telephone Call) - Fig. 6

Prior to an incoming traditional telephone call arriving from a telephone 71, the public Telephone Company's termination point POTSAP 13 and the telephone line may be busy with a computer network communication (94/98-95-96/97 in Fig. 5 or Fig. 10), either between the computer device 16 and the computer network 18; or a computer network telephone call (98-95-97 in Fig. 7 or 8) between any one of the telephones 41, 42, 43, ...4x and a remote telephone 7x; or, in variants with directly connected telephones (51, ...5x in Fig. 12), with computer network telephone calls between the directly connected telephones and a remote telephone 7y.

An incoming traditional telephone call session initiated from a remote telephone 71 results, as part of the V.92 protocol of the preferred embodiment, in the following steps:

• Signals destined for the modem device 38 and forwarded via the splitter modification circuit 34S and 34M from the Public Switched Telephone Network 15 as previously described, which signals flag the modem circuit 38 to place the computer network communication and/or computer network telephone call on hold for the duration of the subsequent telephone conversation (93-92-91 of Fig. 6). Other technologies comparable to V.92 may be applied in other embodiments of the invention, provided they provide a similar functionality; • Splitter PABX-emulator circuit 37S, on detecting ringing signals from the Public Switched Telephone Network 14, forwards a control signal via splitter modification circuit 34S to modem modification circuit 34M as previously described, to cause PABX-emulator circuit 37A to generate ringing signals to the premises telephone network 11, preferably with another cadence than the one used for signaling incoming computer network calls; • PABX-emulator circuit 37A, on detecting an off-hook of the handset of an answering telephone 4x, causes the control circuit 33B to establish a connection between modem modification circuit 34M and the premises telephone network 11 for exchanging regenerated speech signals between the two;

• Subsequently and until the call from the originating calling telephone 71 is terminated the splitter modification circuit 34S receives incoming traditional telephone signals 93 from the Public Switched

Telephone Network 14, transmits them in modified format 92 along the premises telephone network to modem modification circuit 34M, which regenerates the signals as previously described; and transmits the regenerated signals, now in the same format the original analog speech signals 91, via control circuit 33B via PABX-emulator circuit 37A and the premises telephone network 11 to the answering telephone 4x;

• And vice versa for outgoing signals 91 received from the telephone 4x and destined for the calling telephone 71;

• Reception of a "hang-up" or a similar signal by the splitter PBX-emulator circuit 37S from the Public Switched Telephone Network 14 now and at any later point in time during the call, results in the call (93-92-91) being terminated and the state of the dual mode telephone system being reestablished to the one ruling prior to the call.

The V.92 protocol performed by modem circuit 38 ensures, that the previous computer network communication and/or computer network telephone call (94/98) is automatically resumed when the incoming traditional telephone call 93 is terminated, provided the length of the call does not exceed the maximum determined by the Internet Service Provider. In another aspect of the invention, the dual mode telephone system 11 may include facilities for automatically re-establishing the computer network communication (94/98), should it have been broken due to e.g. the time-out of incoming traditional telephone call 93.

In summary, when a user receives an incoming call 93 from a telephone the Public Switched Network 14, while none of the telephones 41, 42, 43, ...4x are being used, the operation of the telephone call will be as if the dual mode telephone system 11 had not been present and the computer device 16 was not occupying the line with computer network traffic.

In yet an alternative embodiment, illustrated in Fig. 14, the telephone signals 93 exchanged by the splitter device 31 with the public communication network 15 may be relayed directly 91 on the premises telephone network 11 without performing the modifications described above.

Simultaneous use of two or more telephones Fig. 12 depicts an alternative preferred embodiment, and illustrates how two or more telephones may simultaneously be used for computer network telephone service, one of them (one of 41, 42, 43, ...4x) being connected to the premises telephone network 11 as described in the preferred embodiment presented above, while the others 5x are directly connected to the subscriber system 12. The description focuses upon aspects where this suite of embodiments deviates from the preceding suite and should be seen in that context.

The directly connected telephone 5x is connected via connection 9 to modem device 32. The embodiment requires a replication set (not shown) of modem PBX circuit 37E, conversion circuit 37, and compression circuit 35 associated with a telephone connection, separate from the connection to the premises telephone network. The compression circuit 35, its replication and the computer device 16 share the modem circuit 38.

Firstly, any one of the telephones 41, 42, 43, ...4x of the premises telephone network 11 may be used to receive an incoming traditional telephone call or to perform a incoming or outgoing computer network call (97-95-98), whether or not the directly connected telephone 5x is active. This call takes place as previously described. Secondly, a directly connected telephone 5x may be used to perform an incoming or outgoing computer network call (97-95-98), whether any of the telephones 41, 42, 43, ...4x of the premises telephone network 11 is active or not. Such calls are handled identically to the way computer network telephone service is handled for the telephones 41 , 42, 43, ...4x, other than that the conversion from analog telephone signals to VoIP are handled by the replicated IP conversion /compression circuit set (not shown), to which the telephone 5x is connected.

In a suite of variants of the above embodiment with more than one directly connected telephone 51, ...5x and where all of the directly connected telephones may be used simultaneously and independently of each other, and simultaneously with any one of the telephones 41, 42, 43,...4x, one replication set (not shown) of the conversion/compression circuit will be required for each directly connected telephones. Furthermore, provided each incoming computer network call is being uniquely identified, multiple incoming computer network conversations may be active at a given point in time.

In yet another suite of variants of any of the above embodiments, the directly connected telephones may permit receiving incoming traditional telephone calls similar to how the telephones 41, 42, 43, ...4x may receive such calls. This may require additional means (not shown), in their simplest form by means of relays and similar circuit.

Claims

1. A system for telephone line sharing comprising a subscriber system, the subscriber system having

• a premises telephone network with connection for at least one telephone; • an access point to a public telephone network;

• a modem converter connected to the premises telephone network with means for switching between an active mode and a passive mode, the modem converter comprising a digitizer and a transceiver, the digitizer being adapted for converting traditional telephone signals to computer network telephone data packets and vice versa, the transceiver being adapted for receiving the computer network telephone data packets and other computer data packets, for converting both kinds of data packets into modified format signals that will not interfere with the transmission of analog telephone signals on the premises telephone network and vice versa, and for transmitting the modified format signals on the premises telephone network, signals representing computer network telephone data being transmitted with priority ahead of signals representing other data; • a splitter with a means for switching between a passive mode and an active mode of operation, the splitter serving in passive mode to provide a direct connection between the premises telephone network and the access point, the splitter serving in active mode to receive the modified format signals, to convert these back to regenerated data packets and to transmit the regenerated data packets to the access point; • the modem converter being adapted for transmitting a control signal to the splitter to make the splitter switch between its active mode and its passive mode according to the switching of the modem converter.

2. The system according to claim 1, wherein the modem converter comprises a computer interface connected to the transceiver.

3. The system according to claim 1, wherein the modem converter comprises a computer modem connected to the transceiver.

4. The system according to claim 1, wherein the splitter is adapted for in the active mode preventing analog telephone signals from the premises telephone network from reaching the access point.

5. The system according to claim 1, wherein the subscriber system comprises means for generating and transmitting to the premises telephone network ring signals, busy tone signals, and means for performing off/on-hook detection, for detecting dual-tone multi-frequency (DTMF) signals and for converting these to digitized number signals.

6. The system according to any of the preceding claims, wherein the subscriber system comprises means to respond to an incoming traditional telephone call by suspending a session of computer network communication for the duration of the incoming traditional call, the system allowing the

5 resumption of the computer network session without re-initialization once the incoming call has terminated.

7. The system according to any of the preceding claims, wherein the conversion of the signals to the modified format takes place by changing the frequency, by use of side-bands, or similar.

10

8. The system according to any of the preceding claims, wherein the premises telephone network comprises telephone wires in a random tree structure.

9. The system according to any of the preceding claims, wherein the modem converter comprises a 15 computer device.

10. The system according to any of the preceding claims, wherein the modem converter converts the analog telephone signals according to the Voice-over-Internet-Protocol (VoIP) and performs computer communication according to the TCP/IP protocol.

20

11. The system according to any of the preceding claims, wherein the modem converter comprises means for noise suppression and white noise generation, means for detecting and substituting lost or timed-out speech packets, and means for echo cancellation.

25 12. The system according to any of the preceding claims, wherein the modem converter comprises means for handling speech compression in accordance with the international standard G.711, G.723a and G.729.1 protocols.

13. The system according to any of the preceding claims, wherein the modem converter comprises 30 means for supplying power to the system.

14. The system according to any of the preceding claims, wherein the modem converter comprises means for, in the passive mode, electrically disconnecting the premises telephone network from remaining part of the modem converter, preferably a relay, and means for, in the active mode,

35 establishing an electrical connection with the premises telephone network, preferably a relay.

15. The system according to any of the preceding claims, wherein the modem converter comprises a telephone connection with a further digitizer for conversion of analog telephone signals to computer network telephone signals and connected to the transceiver.

16. The system according to any of the preceding claims, comprising a communication link to the public communication network and a host system connected to the public communication network, preferably via a telephone line carrying a traditional analog telephone voice channel.

17. The system according to claim 16, wherein the host system comprises means for receiving from the public communication network incoming computer network telephone signals destined to the subscriber system and for transmitting computer network telephone signals with priority over computer network signals via the public communication network to the subscriber system.

18. A dual mode telephone system comprising a subscriber and a host system; the subscriber system having at least one telephone; means for converting traditional telephone signals from/to said telephones to/from computer network telephone signals and for exchanging said computer network telephone signals with a public communication network; browser software in at least one computer device; means in at least one of the computer devices for a more efficient distribution and storage of content to/from the public communication network from/to said browser software; first communication means for establishing a connection between the at least one telephone and the at least one computer device, and the public communication network; and second communication means for establishing connection(s) with the at least one computer device(s); communication means for establishing connection(s) with said telephone(s); and further means for transmitting outgoing computer network telephony signals with priority over computer device to computer network signals via the public communication network to the host system, which relays said signals to the public communication network, the host system having third communications means for connecting said host system and the public communication network; and means for, together with the subscriber system, a more efficient distribution and storage of content to/from the public communication network from/to said browser software, and further means for receiving from the public communication network incoming computer network telephony signals destined the one or more telephone(s) and/or computer network signals destined the at least one computer device(s) and transmitting said computer network telephony signals with priority over the computer device to computer network signals via the public communication network to the subscriber system, wherein said first communication means being capable of accommodating two or more full-duplex bi-directional connections between said at least one telephone and/or said at least one computer device, and said public communication network at the same time, the dual mode telephone system reducing response times to/from browser software of the at least one computer device from/to the public communication network and allowing any of the telephones being used simultaneously for computer network telephone service while still maintaining the service level, stability, and connectivity of traditional telephone calls and computer network connections. 5

19. A method for telephone line sharing in a subscriber system, the subscriber system having a premises telephone network with at least one telephone; an access point to a public telephone network; a modem converter with means for switching between an active mode and a passive mode, with a connection to the premises telephone network and with a computer data connection, adapted for, in its

10 active mode, receiving via the premises telephone network traditional telephone signals and for converting these to computer network telephone data packets and for receiving via the computer data connection computer data packets; and a splitter with a means for switching between a passive mode and an active mode of operation; comprising the steps of switching the modem converter to active mode, transmitting from the modem converter a control signal to the splitter to switch the splitter to its

15 active mode; modifying in the modem converter both kinds of data packets to a modified format that will not interfere with the transmission of analog telephone signals and vice versa, retransmitting the modified format signals on the premises telephone network, signals representing computer network telephone data being transmitted with priority over signals representing other data; receiving in the splitter the modified format signals and converting these back to regenerated data packets; and

20 transmitting the regenerated data packets to the access point.

20. The method according to claim 19, comprising preventing in the active mode of the splitter analog telephone signals from the premises telephone network from reaching the access point.

25 21. The method according to claim 19, comprising responding in the subscriber system to an incoming traditional telephone call by suspending a session of computer network communication for the duration of the incoming traditional call, and the resumption of the computer network session without re-initialization once the incoming call has terminated.

30 22. The method according to claim 19, comprising the conversion of the signals to the modified format by changing the frequency, by use of side-bands or similar.

23. The method according to claim 19, comprising the conversion in the modem converter of the analog telephone signals according to the Voice-over-Internet-Protocol (VoIP) and the performing of 35 the computer communication according to the TCP/IP protocol.

24. The method according to claim 19, comprising compression in the modem converter of speech in accordance with the international standard G.711, G.723a and G.729.1 protocols.

25. The method according to claim 19, comprising electrically disconnecting the premises telephone network by the modem converter and from the remaining part of the modem converter, preferably by a relay, and establishing an electrical connection between the premises telephone network and the access point, preferably by a relay.

26. The method according to claim 19, comprising launching, by the switching of the modem converter into active mode, a command to the splitter, that causes the splitter to electrically isolate the premises telephone network from the access point, and to establish an electrical connection to feed power to the remaining part of the premises telephone network.

27. The method according to claim 19, comprising establishing a communication link to the public communication network and providing a host system connected to the public communication network.

28. The method according to claim 19, comprising expanding the bandwidth of the telephone line for reducing response times to browser software of the computer device by more efficiently downloading from a public communication network to browser software of the computer device and by a more efficient storage of content.

29. The method according to claim 27, comprising receiving in the host system incoming computer network telephone signals from the public communication network and destined to the subscriber system and forwarding via the public communication network and to the subscriber system computer network telephone signals with priority over computer network signals.

30. The method according to claim 27, comprising responding to the detection of a telephone line being busy with a computer network communication by transferring an incoming traditional telephone call away from the telephone line; converting the telephone call to a computer network telephone call; and forwarding the converted call to the host system.

31. The method according to claim 19, comprising, on switching from passive mode to active mode, transmitting to the access point a call-forwarding instruction for telling the public communication network to forward any incoming calls to an IP Gateway for conversion to computer network telephone service to be destined to an IP-address assigned to the premises computer network termination.

32. The method according to claim 19, comprising, on switching from active mode to passive mode, transmitting to the access point an instruction for telling the public communication network to clear any call-forwarding instructions and henceforth to transmit any incoming telephone calls to the access

5 point as traditional phone calls.

33. The method according to claim 27, comprising responding to a request for a new connection in form of a traditional incoming telephone call from the public communication network, by a first communication means putting other connections on hold for the duration of the new call; the splitter

10 device relaying signals received from the public communication network unmodified to the premises network and vice versa and at the same time for signals in the opposite direction; and, once the incoming traditional telephone call has terminated, the first communication means automatically resuming other connections.

15 34. A method comprising the steps of establishing a first full-duplex bi-directional computer network telephone connection from a public communication network to a subscriber system to which one or more telephones is/are connected; converting in said subscriber system traditional telephone signals from/to connected telephones to/from computer network telephone signals; converting in the public communication network an incoming traditional telephone call to a computer network telephone call

20 destined the said telephone or vice versa for an outgoing call originated from said telephone; establishing a second full-duplex bi-directional connection between at least one computer device and the public communication network, the establishment of said second connection not causing said first connection to be interrupted; and simultaneously transmitting first communication signal via said first connection and a second communication signal via said second connection via the same telephone 5 line.