The SLK2511B is a single chip multirate transceiver IC used to derive high-speed timing signals for SONET/SDH based equipment. The chip performs clock and data recovery, serial-to-parallel/parallel-to-serial conversion and frame detection function conforming to the SONET/SDH standards. The device can be configured to operate under OC-48, OC-24, OC-12, or OC-3 data rates through the rate selection pins or the autorate detection function. An external reference clock operating at 155.52 MHz or 622.08 MHz is required for the recovery loop, and it also provides a stable clock source in the absence of serial data transitions.