An apparatus for and a method of interfacing a host to a modem. Data is transferred between the host and the modem via a serial interface. The modem provides the physical layer implementation functions (i.e., transmission and reception functions) in addition to providing low level MAC layer function...http://www.google.es/patents/US6690719?utm_source=gb-gplus-sharePatente US6690719 - Host to modem interface
