System and method for performing telephone line-in-use detection, extension pick-up detection, and remote hang-up detection in a modem

Abstract

The invention is directed to multi-line data exchange systems. The invention comprises one or more telephony devices, each coupled to one or more telephone communication lines, such as a standard telephone line, T1 line, T3 line, coaxial cable, or fiber optic line. The telephony devices are equipped with data communication interfaces. These interfaces allow the telephony devices to operate on more than one telephone communication line. The telephone communication lines operate on several bandwidths, including an audio bandwidth. The telephony devices can communicate among themselves apart from the audio bandwidth of the telephone communication lines. When another telephony device is activated or ceases use on one of the telephone communication lines, the telephony devices detect this event and communicate information on the usage of the telephone communication line on the telephone communication lines at a bandwidth other than the audio bandwidth used in voice communications.