A multirate transceiver IC for four-wire full-duplex data transmission

A CMOS IC transceiver for full-duplex data transmission at 14 data rates is described. At the highest rate of 72 kb/s, two of these chips communicate on a four-wire twisted-pair telephone loop with loss at 36 kHz of up to 48 dB. The chip performs all line driving, timing recovery, and data recovery functions with only 11 passive external line interface components. The transceiver can converge on all digital data service (DDS) lines. sending and receiving unscrambled data without the need for a training sequence. The chip was fabricated in a 2- mu m, double-polysilicon, double-metal process with an area of 49 mm/sup 2/. Power consumption is 200 mW from the single 5-V supply.<
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