The DS2181A is designed for use in CEPT networks and supports all logical requirements of CCITT Red Book recommendations G.704, G.706, and G.732. The transmit side generates framing patterns and CRC4 codes, formats outgoing channel and signaling data, and produces network alarm codes when enabled. The receive side decodes the incoming data and establishes frame, CAS multiframe, and CRC4 multiframe alignments. Once synchronized, the device extracts channel, signaling, and alarm data.

A serial port allows access to 14 on-chip control and status registers in the processor mode. In this mode, a host processor controls features such as error logging, per-channel code manipulation, and alteration of the receive synchronizer algorithm.

The hardware mode is intended for preliminary system prototyping and/or retrofitting into existing systems. This mode requires no host processor and disables special features available in the processor mode.