A T1-based DSP modem for interfacing voice and packet networks

A packet-switched data network (PSDN) with dial-in or dial-out capability requires a large number of interfaces to the public switched telephone network (PSTN). A T1 trunk connected to an X.25 trunk by a multiple digital signal processing modem is proposed for this interface in place of individual telephone lines, modems and computer cables. The design and performance for this type of modem, meeting the 212A standard, is presented. A simple hardware design using an EPROM DSP chip is described to illustrate the compact implementation possible for such a circuit-switched/packet-switched network interface.<
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