APPLICATION NOTE 3111

Interfacing the DS3144 Framer with the DS3154 Line Interface Unit (LIU)


Abstract: The DS3144 has four independent DS3/E3 framers on a single die and includes all necessary circuitry to frame and format four separate DS3 or E3 channels. Each framer in this device is independently configurable to support M23 DS3, DS3 C-Bit Parity, or G.751 frame formats with all applicable alarm detection and generation. The DS3144 interfaces to a variety of line interface units (LIUs), microprocessor buses, and other system components without glue logic. The digital data interface to the LIU can be Binary (NRZ) or Bipolar (POS/NEG), and provides internal B3ZS/HDB3 encoders and decoders. The DS3154 quad LIU performs the functions necessary for interfacing at the physical layer to DS3, E3, or STS-1 lines. Each LIU has an independent receive and transmit path and a built-in jitter attenuator. Each port of the DS3154 is independently configurable. The DS3154 has both hardware or CPU bus configuration options.