The CS61574A and CS61575 combine the complete analog transmit and receive line interface for T1 or E1 applications in a low power, 28-pin device operating from a +5V supply. Both devices support processorbased or stand-alone operation and interface with industry standard T1 and E1 framers. The receiver uses a digital Delay-Locked-Loop which is continuously calibrated from a crystal reference to provide excellent stability and jitter tolerance. The CS61574A has a receiver jitter attenuator optimized for minimum delay in switching and transmission applications, while the CS61575 attenuator is optimized for CPE applications subject to AT&T 62411 requirements. The transmitter features internal pulse shaping and a matched, constant impedance output stage to insure signal quality on mismatched, poorly terminated lines.