Data transmission equipment

摘要

The data transmission unit or equipment that is the subject of the invention is a card in the ND system incorporating the following parts: A modulator-demodulator complying with the V22 and V22Bis recommendations of the CCITT that permits duplex data transmission over a 2 or 6 wire dedicated line. A control unit for the switched telephone network (STN),that permits direct connection to the STN of the modem and the associated telephone without the requirement for the optional UCRC or V25-Bis unit. <IMAGE>