View ds2154 datasheet:

DS2154 Enhanced E1 Single Chip Transceiver www.dalsemi.com FEATURES PACKAGE OUTLINE Complete E1(CEPT) PCM-30/ISDN-PRI transceiver functionality Onboard long- and short-haul line interface for clock/data recovery and waveshaping 32-bit or 128-bit crystal-less jitter attenuator Generates line build outs for both 120?=and 75?=lines Frames to FAS, CAS, and CRC4 formats Dual onboard two-frame elastic store slip buffers that can connect to asynchronous backplanes up to 8.192 MHz 8-bit parallel control port that can be used directly on either multiplexed or non-multiplexed buses Extracts and inserts CAS signaling Detects and generates Remote and AIS alarms Programmable output clocks for Fractional E1, H0, and H12 applications Fully independent transmit and receive