CA1331648C - Multimode modem - Google Patents
Multimode modemInfo
- Publication number
- CA1331648C CA1331648C CA000599496A CA599496A CA1331648C CA 1331648 C CA1331648 C CA 1331648C CA 000599496 A CA000599496 A CA 000599496A CA 599496 A CA599496 A CA 599496A CA 1331648 C CA1331648 C CA 1331648C
- Authority
- CA
- Canada
- Prior art keywords
- modem
- multimode
- types
- sequence
- variety
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
- H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Telephonic Communication Services (AREA)
- Communication Control (AREA)
Abstract
Abstract of the Disclosure The modem communicates with a variety of modem types employing differing initial handshake signals.
The multimode modem sands a sequence of signals corresponding to the variety of modem type handshake signals and the sequence terminates when the multimode modem receives an appropriate response identifying a particular one of the variety of modem types.
The multimode modem sands a sequence of signals corresponding to the variety of modem type handshake signals and the sequence terminates when the multimode modem receives an appropriate response identifying a particular one of the variety of modem types.
Description
i33~ 648 0688w MULTIMODE MODEM
Backqrolmd of the Invention This invention relates to multimode modems.
It is desirable for a modem to be able to interwork with V.32 and with V.22bis and V.22 modems on the public switched telephone network. It is also desirable that the modem automatically select the data rate and mode in which to operate. Further, any interworking procedure of the multimode modem should be compatible with various implementations of both standards.
An interworking procedure has been described which, for the multimode answer modem, invo}ved sending the initial tone for the V.32 procedure (AC) and the initial tone for the V.22bis procedure (UNSCRl at }200 bps) simultaneou~ly. See, "A Proposed Appendix to Recommendation V.32: Interworking Procedure With ~ V.22bis and V.32 Modems", delayed contribution to D-30 -~ to CCITT Study Group XVII, April 1986.
~ As described in this D-30 document, handshaking tones for both V.32 and V.22bis modul~ation modes are transmitted;~because the~tot~al power is restricted, the tones~for each modulation~method are less powerful than - ~ :
~ the~normal singl~-mode~interworking. This power `M~ 25 ~restr~i;6tion poses~ a potential problem after a multimode ~modem has detected the modulation method of the other modem~and ne~eds~to ~emoveithe`other tones a~d increase the power of the correct signalling tones. A modem designed to V.22bis~or~V.~32 and~not to operation with a ` 30~ multimode procedure~as~described in the D-30 document might not~operate;proper~ly through this transition.
Further,~ a-modem constructed to conform only to V.32, might~not reject the additional tones used by a ~ ``: :
. ~: . ' .
~:
Backqrolmd of the Invention This invention relates to multimode modems.
It is desirable for a modem to be able to interwork with V.32 and with V.22bis and V.22 modems on the public switched telephone network. It is also desirable that the modem automatically select the data rate and mode in which to operate. Further, any interworking procedure of the multimode modem should be compatible with various implementations of both standards.
An interworking procedure has been described which, for the multimode answer modem, invo}ved sending the initial tone for the V.32 procedure (AC) and the initial tone for the V.22bis procedure (UNSCRl at }200 bps) simultaneou~ly. See, "A Proposed Appendix to Recommendation V.32: Interworking Procedure With ~ V.22bis and V.32 Modems", delayed contribution to D-30 -~ to CCITT Study Group XVII, April 1986.
~ As described in this D-30 document, handshaking tones for both V.32 and V.22bis modul~ation modes are transmitted;~because the~tot~al power is restricted, the tones~for each modulation~method are less powerful than - ~ :
~ the~normal singl~-mode~interworking. This power `M~ 25 ~restr~i;6tion poses~ a potential problem after a multimode ~modem has detected the modulation method of the other modem~and ne~eds~to ~emoveithe`other tones a~d increase the power of the correct signalling tones. A modem designed to V.22bis~or~V.~32 and~not to operation with a ` 30~ multimode procedure~as~described in the D-30 document might not~operate;proper~ly through this transition.
Further,~ a-modem constructed to conform only to V.32, might~not reject the additional tones used by a ~ ``: :
. ~: . ' .
~:
2 1 3 3 ~ 6 4 8 604l2-l956 multimode modem to sense for a V.22bis modulation mode. As such, there is a possibility that a multimode modem built upon the algorithm described in the document D-30 might not operate with some implementations of V.32. .
Summarv of the Invention According to a broad aspect of the invention there is provided a multimode modem for communicating with a variety of modem types employing different initial handshake signals, comprising: circuitry for sending a sequence of signals corresponding to the variety of modem type handshake signals and for transmitting the sequence when the multimode modem receives a response that identifies a particular one of the variety of modem types; and circuity for determining the particular type of modem ~ -from the received response, said determining being made simultaneously for at least two of said modem types. ~- -According to another broad aspect of the invention there is provlded a method for operating a multimode modem of the kind ~ :
that communicates with a variety of modem types employing ~-different initial handshake signals, comprising: sending a ~
sequence of signals corresponding to the variety of modem type .
handshake signals and terminating the sequence when the multimode modem recelves a response that identifies a particular one of the variety of modem types~;:and determining, simultaneously for at : -least two of said modem types, the particular type of modem from . .
the received response. ~
, ~
~- 133~.648 2a 60412-1956 In a preferred embodiment, the multimode modem is adapted to interwork with V.32 and V.22bis and V.22 modems on the public switched telephone network.
The multimode modem of the invention utilizes a sequential technique to detect the modulation method of another modem with which to communicate. This technique defines an initial operating procedure in which the initial tones of the V.32 and then V.22bis standards are tried sequentially instead of simultaneously (or in parallel~ as described in the D-30 document.
The training procedure, after first seeing the initial tone, will ~ -meet the respective modem standards and thus will be much more -~
robust to the method of implementation of the respective single mode modems. Furthermore, the sequential technique of the present invention may be more accurate than the parallel algorithm described in the D-30 document. This procedure can also be used -`
; ~after the initial connection to change the operating modes from -~;~ the current mode to one of the other modes it is capable of , :: ~
~d~ supporting.
. .
`:`` ~: :
`' '~: ' ~ ` ~
` ` r~ ';- ` t~6 `-~
133~ ~8 Brief DescriPtion of the Drawinq Fig. l is a block diagram of the multimode modem disclosed herein;
Fig. 2 is a block diagram o~ the signal 5 detection block of Fig. l;
Figs. 3a and 3b are schematic illustrations of a multimode call training sequence according to the --invention; and Figs. 4a and ib illustrate multimode answer 10 training sequences.
Descri~tion of the Preferred Embodiment The present invention is a modification of a single mode V.32 Model 2260 modem manufactured by the Codex Corporation of Canton, Massachusetts. This modem ~
; 15 includes a microprocessor chip, Model 6809 manufactured - by the Motorola Corporation. The software driving this microprocessor was modified in the implementation of the preferred embodiment of the present invention.
The~multimode modem of the invention incorporating both V.32 and V.22bis modes of operation can interwork at 9600 and 480Q bits per second with a V.32 modem and ~at 240~0 and }200 bits~per second with a V.22bis modem and at~l200 bits;per~second with a V~.22/212a modem,~automatically selecting the correct --25~ N de.~
The muitimode modem of the;invention is shown in Fig. l. A miaroprocessor 10 controls the functi!on,ajlity o th~ other blocks. The micFoprocessor lO~selects either a V.32 modulator 12 or a V.22bis 3Q~modulator~14 to;connect~to a~telephone 1ine interface 16 and~to~a DTE `interface~18~ The microprocessor lO also selects which~of~demodulators~20 and 22 to use on the input~siqnal and;~to~connect to the DTE interface 18.
The~oigntl detection~àpparatus 24 provides information ~: :
~ , to the microprocessor lo as to the type of signal being received. The apparatus 24 can determine if any of the following signals are present: 600 Hz and 3000 Hz tones (AC), an 1800 Hz tone (AA), a 2250 Hz tone, a 2225 Hz 5 tone, a V.22bis modulated alternating sequence (SI), a V.22bis modulated scrambled l's pattern, or if no signal is present, as shown in Fig. 2. The microprocessor 10 selects the type of modulation to be used and the signal to be sent by the modem. As the calling modem it will 10 not activate either modulator until it has determined the mode of operation to follow. The operation of a calling multimode modem will now be described in conjunction with Figs. 3a and 3b. After connecting to a line the multimode modem will initially remain quiet.
15 The multimode modem will be conditioned to detect one or two incoming tones at frequencies of 600 Hertz and 3,000 Hertz and an unscrambled ones V.22bis signal in the high channel (2250 Hertz). If 600 Hertz and/or 3,000 Hertz tones are received from an answering modem, the 20 multimode modem will continue the handshake sequence in accordance with V.32 and commence transmission of a repetitive carrier state AA. If unscrambled ones at 1200 bits/sec~nd in the high band (as per Y.22bis sections 2.1 and 2.4) is received from the answering 25 modem, then the multimode modem will condition itself ~for operation in accordance with V.22bis, transmitting in the low band and receiving in the high band. ~he handshake~sequence wiil,be qompleted in accordance with V.22bis (section 6.3.1.1.1 or 6.3.1.2.1).
~ 30 As the answer modem, the V.32 initial training `~ sequence is sent first and if there has been no response ~ after a time period, the V.22bis initial training :~` seguence is sent. Since the V.32 signal is the first on- sent, two multimlde modems will interwork in the . ...
133~ ~8 V.32 mode, which is the highest, and hence the most desirable rate. The operation of an answering multimode modem will now be discussed in conjunction with Figs. 4a and 4b. After connecting to the line, the multimode -5 modem will transmit the recommendation V.~5 answer sequence. Then the modem will transmit alternate carrier states A and C. The multimode modem will be conditioned to detect an incoming tone at 1800 Hertz.
If the 1800 Hertz tone is received from the calling 10 modem, then the multimode modem will continue the training sequence in accordance with V.22 section 5.4.2. If there has been no signal received after a period of five seconds, then the multimode modem will ~
cease transmitting AC and start to transmit a tone at -15 2250 Hertz. The multimode modem will be conditioned to detect a V.22bis signal in the low channel as well as a tone at 1800 Hertz. If a low channel signal is received from the calling modem, then the multimode modem will condition itself to receive in the low channel and 20 transmit in the high channel and continue the handshake sequence in accordance with V.22bis (section 6.3.1.1.2 or 6.3.1.2.2). If a tone at 1800 Hertz is received, then the mult~imode modem will cease transmitting the ~-~ 2250 Hertz tone and start transmitting alternating 25 carrier states A and C, the multimode modem will attempt to follow the remainder of the V.32 training sequence.
~`
`, :
"~ . ~ :, ~ .
;`,
Summarv of the Invention According to a broad aspect of the invention there is provided a multimode modem for communicating with a variety of modem types employing different initial handshake signals, comprising: circuitry for sending a sequence of signals corresponding to the variety of modem type handshake signals and for transmitting the sequence when the multimode modem receives a response that identifies a particular one of the variety of modem types; and circuity for determining the particular type of modem ~ -from the received response, said determining being made simultaneously for at least two of said modem types. ~- -According to another broad aspect of the invention there is provlded a method for operating a multimode modem of the kind ~ :
that communicates with a variety of modem types employing ~-different initial handshake signals, comprising: sending a ~
sequence of signals corresponding to the variety of modem type .
handshake signals and terminating the sequence when the multimode modem recelves a response that identifies a particular one of the variety of modem types~;:and determining, simultaneously for at : -least two of said modem types, the particular type of modem from . .
the received response. ~
, ~
~- 133~.648 2a 60412-1956 In a preferred embodiment, the multimode modem is adapted to interwork with V.32 and V.22bis and V.22 modems on the public switched telephone network.
The multimode modem of the invention utilizes a sequential technique to detect the modulation method of another modem with which to communicate. This technique defines an initial operating procedure in which the initial tones of the V.32 and then V.22bis standards are tried sequentially instead of simultaneously (or in parallel~ as described in the D-30 document.
The training procedure, after first seeing the initial tone, will ~ -meet the respective modem standards and thus will be much more -~
robust to the method of implementation of the respective single mode modems. Furthermore, the sequential technique of the present invention may be more accurate than the parallel algorithm described in the D-30 document. This procedure can also be used -`
; ~after the initial connection to change the operating modes from -~;~ the current mode to one of the other modes it is capable of , :: ~
~d~ supporting.
. .
`:`` ~: :
`' '~: ' ~ ` ~
` ` r~ ';- ` t~6 `-~
133~ ~8 Brief DescriPtion of the Drawinq Fig. l is a block diagram of the multimode modem disclosed herein;
Fig. 2 is a block diagram o~ the signal 5 detection block of Fig. l;
Figs. 3a and 3b are schematic illustrations of a multimode call training sequence according to the --invention; and Figs. 4a and ib illustrate multimode answer 10 training sequences.
Descri~tion of the Preferred Embodiment The present invention is a modification of a single mode V.32 Model 2260 modem manufactured by the Codex Corporation of Canton, Massachusetts. This modem ~
; 15 includes a microprocessor chip, Model 6809 manufactured - by the Motorola Corporation. The software driving this microprocessor was modified in the implementation of the preferred embodiment of the present invention.
The~multimode modem of the invention incorporating both V.32 and V.22bis modes of operation can interwork at 9600 and 480Q bits per second with a V.32 modem and ~at 240~0 and }200 bits~per second with a V.22bis modem and at~l200 bits;per~second with a V~.22/212a modem,~automatically selecting the correct --25~ N de.~
The muitimode modem of the;invention is shown in Fig. l. A miaroprocessor 10 controls the functi!on,ajlity o th~ other blocks. The micFoprocessor lO~selects either a V.32 modulator 12 or a V.22bis 3Q~modulator~14 to;connect~to a~telephone 1ine interface 16 and~to~a DTE `interface~18~ The microprocessor lO also selects which~of~demodulators~20 and 22 to use on the input~siqnal and;~to~connect to the DTE interface 18.
The~oigntl detection~àpparatus 24 provides information ~: :
~ , to the microprocessor lo as to the type of signal being received. The apparatus 24 can determine if any of the following signals are present: 600 Hz and 3000 Hz tones (AC), an 1800 Hz tone (AA), a 2250 Hz tone, a 2225 Hz 5 tone, a V.22bis modulated alternating sequence (SI), a V.22bis modulated scrambled l's pattern, or if no signal is present, as shown in Fig. 2. The microprocessor 10 selects the type of modulation to be used and the signal to be sent by the modem. As the calling modem it will 10 not activate either modulator until it has determined the mode of operation to follow. The operation of a calling multimode modem will now be described in conjunction with Figs. 3a and 3b. After connecting to a line the multimode modem will initially remain quiet.
15 The multimode modem will be conditioned to detect one or two incoming tones at frequencies of 600 Hertz and 3,000 Hertz and an unscrambled ones V.22bis signal in the high channel (2250 Hertz). If 600 Hertz and/or 3,000 Hertz tones are received from an answering modem, the 20 multimode modem will continue the handshake sequence in accordance with V.32 and commence transmission of a repetitive carrier state AA. If unscrambled ones at 1200 bits/sec~nd in the high band (as per Y.22bis sections 2.1 and 2.4) is received from the answering 25 modem, then the multimode modem will condition itself ~for operation in accordance with V.22bis, transmitting in the low band and receiving in the high band. ~he handshake~sequence wiil,be qompleted in accordance with V.22bis (section 6.3.1.1.1 or 6.3.1.2.1).
~ 30 As the answer modem, the V.32 initial training `~ sequence is sent first and if there has been no response ~ after a time period, the V.22bis initial training :~` seguence is sent. Since the V.32 signal is the first on- sent, two multimlde modems will interwork in the . ...
133~ ~8 V.32 mode, which is the highest, and hence the most desirable rate. The operation of an answering multimode modem will now be discussed in conjunction with Figs. 4a and 4b. After connecting to the line, the multimode -5 modem will transmit the recommendation V.~5 answer sequence. Then the modem will transmit alternate carrier states A and C. The multimode modem will be conditioned to detect an incoming tone at 1800 Hertz.
If the 1800 Hertz tone is received from the calling 10 modem, then the multimode modem will continue the training sequence in accordance with V.22 section 5.4.2. If there has been no signal received after a period of five seconds, then the multimode modem will ~
cease transmitting AC and start to transmit a tone at -15 2250 Hertz. The multimode modem will be conditioned to detect a V.22bis signal in the low channel as well as a tone at 1800 Hertz. If a low channel signal is received from the calling modem, then the multimode modem will condition itself to receive in the low channel and 20 transmit in the high channel and continue the handshake sequence in accordance with V.22bis (section 6.3.1.1.2 or 6.3.1.2.2). If a tone at 1800 Hertz is received, then the mult~imode modem will cease transmitting the ~-~ 2250 Hertz tone and start transmitting alternating 25 carrier states A and C, the multimode modem will attempt to follow the remainder of the V.32 training sequence.
~`
`, :
"~ . ~ :, ~ .
;`,
Claims (16)
1. A multimode modem for communicating with a variety of modem types employing different initial handshake signals, comprising:
circuitry for sending a sequence of signals corresponding to the variety of modem type handshake signals and for transmitting the sequence when the multimode modem receives a response that identifies a particular one of the variety of modem types; and circuity for determining the particular type of modem from the received response, said determining being made simultaneously for at least two of said modem types.
circuitry for sending a sequence of signals corresponding to the variety of modem type handshake signals and for transmitting the sequence when the multimode modem receives a response that identifies a particular one of the variety of modem types; and circuity for determining the particular type of modem from the received response, said determining being made simultaneously for at least two of said modem types.
2. The multimode modem of claim 1 wherein the variety of modem types include V.32 and V.22bis.
3. The multimode modem of claim 2 where a handshake signal for the V.32 modem type is the first one transmitted.
4. The multimode modem of claim 1 further adapted to cause the sequence of hanshake signals to be sent at a predetermined time after said connection is made so that the operating mode of said multimode modem can be changed.
5. The multimode modem of claim 1 wherein said multimode modem is a calling modem and said response that identifies a particular modem type is received from an answering modem, and further comprising circuitry for causing said multimode modem to establish a connection with said answering modem, and to operate in a mode that corresponds to said particular type of said answering modem.
6. The multimode modem of claim 1 wherein said circuitry for determining determines said particular type of modem simultaneously for all of said modem types.
7. The multimode modem of claim 1 wherein said circuitry for determining determines said particular type of modem simultaneously with said sending of said sequence and receiving said response.
8. The multimode modem of claim 1 wherein said circuitry for determining comprises at least two filters, which correspond to said at least two modem types, that are adapted to simultaneously receive said response, said filters producing output signals that indicate said particular type of modem.
9. A method for operating a multimode modem of the kind that communicates with a variety of modem types employing different initial handshake signals, comprising:
sending a sequence of signals corresponding to the variety of modem type handshake signals and terminating the sequence when the multimode modem receives a response that identifies a particular one of the variety of modem types; and determining, simultaneously for at least two of said modem types, the particular type of modem from the received response.
sending a sequence of signals corresponding to the variety of modem type handshake signals and terminating the sequence when the multimode modem receives a response that identifies a particular one of the variety of modem types; and determining, simultaneously for at least two of said modem types, the particular type of modem from the received response.
10. The method of claim 9 wherein the variety of modem types include V.32 and V.22bis.
11. The method of claim 10 further comprising transmitting a handshake signal for the V.32 modem type before transmitting a handshake signal for the V.22bis modem type.
12. The method of claim 9 wherein said multimode modem is a calling modem and said response that identifies a particular modem type is received from an answering modem, and further comprising causing said multimode modem to establish a connection with said answering modem, and to operate in a mode that corresponds to said particular type of said answering modem.
13. The method of claim 12 further comprising causing the sequence of handshake signals to be sent at a predetermined time after said connection is made so that the operating mode of said multimode modem can be changed.
14. The method of claim 9 wherein said determining is made simultaneously for all of said modem types.
15. The method of claim 9 wherein said determining is made simultaneously with said sending of said sequence and receiving said response.
16. The method of claim 9 wherein said determining comprises simultaneously applying said response to at least two filters, which correspond to said at least two modem types, said filters producing output signals that indicate said particular type of modem.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US07/192,952 US4931250A (en) | 1988-05-12 | 1988-05-12 | Multimode modem |
| US192,952 | 1988-05-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1331648C true CA1331648C (en) | 1994-08-23 |
Family
ID=22711703
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000599496A Expired - Lifetime CA1331648C (en) | 1988-05-12 | 1989-05-11 | Multimode modem |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4931250A (en) |
| EP (1) | EP0416013B1 (en) |
| JP (1) | JP2996994B2 (en) |
| CA (1) | CA1331648C (en) |
| DE (1) | DE68925815T2 (en) |
| FI (1) | FI905579A0 (en) |
| HK (1) | HK1009320A1 (en) |
| WO (1) | WO1989011183A1 (en) |
Families Citing this family (75)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20010050943A1 (en) * | 1989-08-03 | 2001-12-13 | Mahany Ronald L. | Radio frequency communication network having adaptive communication parameters |
| US7606575B2 (en) * | 1988-08-04 | 2009-10-20 | Broadcom Corporation | Remote radio data communication system with data rate switching |
| JPH0817428B2 (en) * | 1988-11-22 | 1996-02-21 | 株式会社日立製作所 | Modulator / demodulator |
| JP2895895B2 (en) * | 1989-12-29 | 1999-05-24 | シャープ株式会社 | Modem |
| AU7255491A (en) * | 1990-02-02 | 1991-08-21 | Codex Corporation | An interface adapter |
| JP3062215B2 (en) * | 1990-03-30 | 2000-07-10 | 沖電気工業株式会社 | Analog front end circuit |
| JP2511591B2 (en) * | 1990-10-29 | 1996-06-26 | インターナショナル・ビジネス・マシーンズ・コーポレイション | Wireless optical communication system operating method and optical communication system |
| US5418842A (en) * | 1990-11-19 | 1995-05-23 | Exxon Research And Engineering Company | Reduced time remote access method |
| US5105438A (en) * | 1990-12-10 | 1992-04-14 | At&T Bell Laboratories | Remotely accessing intelligent network channel terminating equipment device |
| JPH04287458A (en) * | 1991-03-18 | 1992-10-13 | Fujitsu Ltd | Transmission rate control system for serial interface |
| US5331672A (en) * | 1991-07-09 | 1994-07-19 | General Datacomm, Inc. | Automatic detector and selector of RS-232 or V.35 interface |
| US5202899A (en) * | 1991-08-16 | 1993-04-13 | Rockwell International Corporation | Apparatus for providing dynamic selection of modem protocol to support multiple modem types |
| US5317594A (en) * | 1992-01-13 | 1994-05-31 | General Datacomm, Inc. | Systems for and method of identifying V.fast modem within existing automatic interworking procedure standards |
| JP3231394B2 (en) * | 1992-04-01 | 2001-11-19 | 株式会社リコー | modem |
| US5311578A (en) * | 1992-05-07 | 1994-05-10 | At&T Bell Laboratories | Technique for automatic identification of a remote modem |
| US5491720A (en) * | 1992-05-21 | 1996-02-13 | International Business Machines Corporation | Method and system for automatically determining data communication device type and corresponding transmission rate |
| CA2126319C (en) * | 1992-10-19 | 2000-04-18 | Masami Yabusaki | Mobile communication control method |
| USRE39116E1 (en) | 1992-11-02 | 2006-06-06 | Negotiated Data Solutions Llc | Network link detection and generation |
| EP0596648A1 (en) * | 1992-11-02 | 1994-05-11 | National Semiconductor Corporation | Network link endpoint capability detection |
| EP0596651A1 (en) | 1992-11-02 | 1994-05-11 | National Semiconductor Corporation | Network for data communication with isochronous capability |
| USRE39395E1 (en) | 1992-11-02 | 2006-11-14 | Negotiated Data Solutions Llc | Data communication network with transfer port, cascade port and/or frame synchronizing signal |
| US5349635A (en) * | 1992-11-19 | 1994-09-20 | At&T Bell Laboratories | Half-duplex or full-duplex automode operation for use in data communications equipment |
| FR2699031B1 (en) * | 1992-11-25 | 1995-01-27 | France Telecom | Method for automatic communication in duplex or half-duplex of two pieces of equipment through a telephone line. |
| FR2699030B1 (en) * | 1992-11-25 | 1995-01-27 | France Telecom | Resumption-adaptation method for maintaining duplex communication between two pieces of equipment through a telephone line. |
| WO1994013094A1 (en) * | 1992-11-25 | 1994-06-09 | France-Telecom | Method of automatic duplex or semi-duplex communication for two units via a telephone line |
| US5404394A (en) * | 1993-05-24 | 1995-04-04 | Comsat Corporation | Secure communication system |
| US5450438A (en) * | 1993-07-26 | 1995-09-12 | At&T Corp. | Fallback method to 1200 bits per second for use in mobile radio |
| US5513212A (en) * | 1993-11-15 | 1996-04-30 | At&T Corp. | Conversion of a fax modulation to a data modulation |
| EP0667728B1 (en) * | 1994-01-14 | 1999-11-03 | International Business Machines Corporation | Method for automatically adapting and configuring the speed of an ISDN terminal adapter to either 56 KBPS or 64 KBPS |
| US5446771A (en) * | 1994-01-24 | 1995-08-29 | Motorola, Inc. | Adaptive coherent signal detection method and apparatus |
| US5442629A (en) * | 1994-02-24 | 1995-08-15 | International Business Machines Corporation | Token ring speed detector |
| US5619539A (en) * | 1994-02-28 | 1997-04-08 | International Business Machines Corporation | Data detection methods and apparatus for a direct access storage device |
| US6463132B1 (en) * | 1994-04-27 | 2002-10-08 | Canon Kabushiki Kaisha | Communication system having the capability of selecting an optimum communication mode from a plurality of modes, depending on the type of equipment at a party to be communicated with |
| JP3161910B2 (en) * | 1994-07-26 | 2001-04-25 | シャープ株式会社 | Communication device |
| US5732104A (en) * | 1994-12-14 | 1998-03-24 | Motorola, Inc. | Signalling techniques and device for high speed data transmission over voiceband channels |
| US5533018A (en) | 1994-12-21 | 1996-07-02 | National Semiconductor Corporation | Multi-protocol packet framing over an isochronous network |
| JP2727997B2 (en) * | 1995-01-18 | 1998-03-18 | 日本電気株式会社 | Baud rate mixed transmission system |
| US5550881A (en) * | 1995-04-13 | 1996-08-27 | Motorola, Inc. | Automatic modulation mode selecting unit and method for modems |
| US5809085A (en) * | 1995-06-28 | 1998-09-15 | Motorola Inc. | Apparatus and method for detecting and discriminating various signal types in the presence of impulse distortions |
| US5960035A (en) * | 1995-09-29 | 1999-09-28 | Motorola Inc. | Method and apparatus for load balancing for a processor operated data communications device |
| US5802065A (en) * | 1995-10-23 | 1998-09-01 | Kawasaki Steel Corporation | Data receiving device |
| JP3472035B2 (en) * | 1996-04-19 | 2003-12-02 | キヤノン株式会社 | Facsimile machine |
| US6055268A (en) * | 1996-05-09 | 2000-04-25 | Texas Instruments Incorporated | Multimode digital modem |
| US5805597A (en) * | 1996-06-04 | 1998-09-08 | National Semiconductor Corporation | Method and apparatus for providing low power basic telephony type service over a twisted pair ethernet physical layer |
| US5787116A (en) * | 1996-06-18 | 1998-07-28 | Motorola Inc. | Apparatus and method for detecting amplitude modulated answer back toned signals |
| US5796808A (en) * | 1997-01-09 | 1998-08-18 | Paradyne Corporation | System and method for automatically selecting the mode of communication between a plurality of modems |
| US5852631A (en) * | 1996-06-21 | 1998-12-22 | Paradyne Corporation | System and method for establishing link layer parameters based on physical layer modulation |
| WO1997049228A1 (en) * | 1996-06-21 | 1997-12-24 | Paradyne Corporation | A rapid startup protocol for communication between a plurality of modems |
| WO1997049229A1 (en) * | 1996-06-21 | 1997-12-24 | Paradyne Corporation | System and method for automatically selecting the mode of communication between a plurality of modems |
| US5751796A (en) * | 1996-06-21 | 1998-05-12 | Paradyne Corporation | Rapid startup protocol for communication between a plurality of modems |
| US5822404A (en) * | 1996-09-30 | 1998-10-13 | Intervoice Limited Partnership | System and method for identifying remote communications formats |
| JP3140381B2 (en) * | 1996-10-30 | 2001-03-05 | 松下電送システム株式会社 | Data communication device |
| US5864545A (en) * | 1996-12-06 | 1999-01-26 | Altocom, Inc. | System and method for improving convergence during modem training and reducing computational load during steady-state modem operations |
| US5999979A (en) * | 1997-01-30 | 1999-12-07 | Microsoft Corporation | Method and apparatus for determining a most advantageous protocol for use in a computer network |
| US5940438A (en) | 1997-02-18 | 1999-08-17 | Mitsubishi Electric Information Technology Center America, Inc (Ita) | Universal modem for digital video, audio and data communications |
| US9118387B2 (en) * | 1997-11-03 | 2015-08-25 | Qualcomm Incorporated | Pilot reference transmission for a wireless communication system |
| US7184426B2 (en) * | 2002-12-12 | 2007-02-27 | Qualcomm, Incorporated | Method and apparatus for burst pilot for a time division multiplex system |
| US6381250B1 (en) | 1998-01-23 | 2002-04-30 | Innovative Communications Technologies, Inc. | Capacity allocation system using semi-autonomous network elements to implement and control a transmission schedule |
| US6426959B1 (en) | 1998-01-20 | 2002-07-30 | Innovative Communications Technologies, Inc. | System and method for facilitating component management in a multiple vendor satellite communications network |
| US6236676B1 (en) | 1998-04-17 | 2001-05-22 | Siemens Information And Communication Networks, Inc. | Intelligent adaptive modulation system |
| JPH11331305A (en) * | 1998-05-08 | 1999-11-30 | Sony Corp | Transmitter and transmitting method, receiver and receiving method and providing medium |
| JP4131052B2 (en) | 1998-07-17 | 2008-08-13 | ソニー株式会社 | Imaging device |
| US6804211B1 (en) * | 1999-08-03 | 2004-10-12 | Wi-Lan Inc. | Frame structure for an adaptive modulation wireless communication system |
| US8064409B1 (en) | 1999-08-25 | 2011-11-22 | Qualcomm Incorporated | Method and apparatus using a multi-carrier forward link in a wireless communication system |
| US6621804B1 (en) * | 1999-10-07 | 2003-09-16 | Qualcomm Incorporated | Method and apparatus for predicting favored supplemental channel transmission slots using transmission power measurements of a fundamental channel |
| JP3545662B2 (en) * | 1999-11-22 | 2004-07-21 | シャープ株式会社 | Data communication device and data communication method |
| US6768771B1 (en) * | 2000-05-23 | 2004-07-27 | L3-Communications Corporation | Multimode modem with automatic negotiation of operational mode |
| US6973098B1 (en) | 2000-10-25 | 2005-12-06 | Qualcomm, Incorporated | Method and apparatus for determining a data rate in a high rate packet data wireless communications system |
| US7068683B1 (en) | 2000-10-25 | 2006-06-27 | Qualcomm, Incorporated | Method and apparatus for high rate packet data and low delay data transmissions |
| WO2002041520A2 (en) | 2000-11-15 | 2002-05-23 | Ensemble Communications, Inc. | Improved frame structure for a communication system using adaptive modulation |
| US8009667B1 (en) | 2001-01-16 | 2011-08-30 | Wi—LAN, Inc. | Packing source data packets into transporting packets with fragmentation |
| IL148314A0 (en) * | 2001-03-09 | 2002-09-12 | Mitsubishi Electric Corp | Signal discrimination apparatus and signal discrimination method and transmission equipment |
| US8730991B1 (en) * | 2009-01-28 | 2014-05-20 | Smsc Holdings S.A.R.L. | Device identification using frequency modulated signal bursts |
| US8811200B2 (en) | 2009-09-22 | 2014-08-19 | Qualcomm Incorporated | Physical layer metrics to support adaptive station-dependent channel state information feedback rate in multi-user communication systems |
| US8645601B2 (en) | 2010-06-11 | 2014-02-04 | Smsc Holdings S.A.R.L. | Methods and systems for performing serial data communication between a host device and a connected device |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3716672A (en) * | 1971-08-09 | 1973-02-13 | Design Elements Inc | Modem cbs/cbt interface |
| US3842207A (en) * | 1973-02-27 | 1974-10-15 | Mi2 Inc | Data set control logic |
| US4215243A (en) * | 1978-11-17 | 1980-07-29 | Racal-Vadic Inc. | Automatic modem identification system |
| FR2445079A1 (en) * | 1978-12-20 | 1980-07-18 | Ibm France | METHOD AND DEVICE FOR DETECTING A PSEUDO-RANDOM SEQUENCE OF PHASE CHANGES OF 0O AND 180O OF THE CARRIER IN A DATA RECEIVER |
| US4578796A (en) * | 1983-11-03 | 1986-03-25 | Bell Telephone Laboratories, Incorporated | Programmable multiple type data set |
| US4756007A (en) * | 1984-03-08 | 1988-07-05 | Codex Corporation | Adaptive communication rate modem |
| US4727370A (en) * | 1985-12-17 | 1988-02-23 | Ampex Corporation | Method and system for synchronous handshake generation |
| IT1216206B (en) * | 1986-07-28 | 1990-02-22 | Weltert Alfredo | PHONE BAND MODULATOR-DEMODULATOR APPARATUS FOR THE TRANSCEIVING OF DIGITAL DATA WITH RECOGNITION OF STANDARD COMMUNICATION SYSTEMS BY THE CALLING SYSTEM. |
-
1988
- 1988-05-12 US US07/192,952 patent/US4931250A/en not_active Expired - Lifetime
-
1989
- 1989-05-10 WO PCT/US1989/002017 patent/WO1989011183A1/en active IP Right Grant
- 1989-05-10 EP EP89906560A patent/EP0416013B1/en not_active Expired - Lifetime
- 1989-05-10 JP JP1506299A patent/JP2996994B2/en not_active Expired - Lifetime
- 1989-05-10 DE DE68925815T patent/DE68925815T2/en not_active Expired - Lifetime
- 1989-05-11 CA CA000599496A patent/CA1331648C/en not_active Expired - Lifetime
-
1990
- 1990-11-12 FI FI905579A patent/FI905579A0/en not_active IP Right Cessation
-
1998
- 1998-06-27 HK HK98107181A patent/HK1009320A1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03505272A (en) | 1991-11-14 |
| DE68925815D1 (en) | 1996-04-04 |
| HK1009320A1 (en) | 1999-05-28 |
| WO1989011183A1 (en) | 1989-11-16 |
| EP0416013B1 (en) | 1996-02-28 |
| US4931250A (en) | 1990-06-05 |
| JP2996994B2 (en) | 2000-01-11 |
| EP0416013A1 (en) | 1991-03-13 |
| FI905579A0 (en) | 1990-11-12 |
| EP0416013A4 (en) | 1992-08-26 |
| DE68925815T2 (en) | 1996-10-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1331648C (en) | Multimode modem | |
| US5287401A (en) | Apparatus and method for a modem for detecting a call waiting signal | |
| US5349635A (en) | Half-duplex or full-duplex automode operation for use in data communications equipment | |
| CA2094189E (en) | Technique for automatic identification of a remote modem | |
| US4959847A (en) | Telecommunications device with automatic code detection and switching | |
| US5317594A (en) | Systems for and method of identifying V.fast modem within existing automatic interworking procedure standards | |
| US5144651A (en) | Reduced time remote access method and system | |
| EP0390931B1 (en) | Method of matching operation mode of a modem | |
| US5699414A (en) | Method and apparatus for sharing a single telephone line between a facsimile machine, data modem, telephone answering device, and a person | |
| US6690776B1 (en) | Communication on hold notifier | |
| JP4545946B2 (en) | Method and apparatus for detecting fax calls | |
| CA2171362A1 (en) | Modem communication interoperability with call waiting services | |
| US6731726B1 (en) | Communication on hold | |
| KR100263478B1 (en) | A method for connecting between a modem and a modem | |
| JPH0697980A (en) | Automatic fall back method for modem | |
| JP3384275B2 (en) | Communication terminal device | |
| JP4088443B2 (en) | Communication pending | |
| JP3511839B2 (en) | Communication terminal device | |
| JPH05336257A (en) | Multi-modem controller | |
| JPH0616639B2 (en) | Handshake method | |
| EP1312198A1 (en) | Communication on hold notifier | |
| JPS63236442A (en) | Communication equipment | |
| JPH1041997A (en) | Modulator-demodulator | |
| JPH02206954A (en) | Method and apparatus for handshaking of modem | |
| JPH10290348A (en) | Communication terminal equipment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |
Effective date: 20110823 |