The DS2155 is a software-selectable T1, E1, or J1 single-chip transceiver (SCT) for short-haul and long-haul applications. The DS2155 is composed of a line interface unit (LIU), framer, HDLC controllers, and a TDM backplane interface, and is controlled by an 8-bit parallel port configured for Intel or Motorola bus operations. The DS2155 is pin and software compatible with the DS2156.