描述 Description

The MT8977 is a variant of the MT8976 framer, which has been enhanced to meet ACCUNET? T1.5 wander tolerance (138 UI).

The MT8977 meets ESF and D3/D4 formats, and is compatible with SLC-96 systems.

特性 Features

? D3/D4 or ESF framing and SLC-96 compatible

? Two frame elastic buffer with jitter tolerance improved to 156 UI

? Insertion and detection of A, B, C, D bits, signalling freeze, optional debounce

? Selectable B8ZS, jammed bit (ZCS) or no zero code suppression

? Yellow alarm and blue alarm signal capabilities

? Bipolar violation count, FT error count, CRC error count

? Selectable robbed bit signalling

? Frame and superframe sync. signals, Tx and Rx

? AMI encoding and decoding

? Per channel, overall, and remote loop around

? Digital phase detector between T1 line and ST-BUS

? One uncommitted scan point and drive point

? Pin compatible with MT8976 and MT8979

? ST-BUS compatible

Applications

? DS1/ESF digital trunk interfaces

? Computer to PBX interfaces (DMI and CPI)

? High speed computer to computer data links