The LXT350 and LXT351 are full-featured, fully-integrated transceivers for T1 and E1 short-haul applications. They are software switchable between T1 and E1 operation, and offer pulse equalization settings for all short-haul T1 and E1 line interface (LIU) applications. The LXT350 and LXT351 are identical except for their control interface. The LXT350 provides both a serial I/O port for microprocessor control and a hardware control mode for stand alone operation. The LXT351 offers an Intel- or Motorola-bus compatible parallel I/O port for microprocessor control. Both incorporate advanced crystal-less digital jitter attenuation in either the transmit or receive data path starting at 3 Hz. B8ZS/HDB3 encoding/decoding and unipolar or bipolar data I/O are available. Both LIUs provide loss of signal monitoring and a variety of diagnostic loopback modes.