This EE-Note describes how to interface Blackfin® processors to standard T1 or E1 encoded signals. The proposed template assumes that a Blackfin processor is functionally located between two T1/E1 streams to perform the required processing, such as line echo canceling. However, the Blackfin processor can be adapted easily to other functional architectures. As shown in this EE-Note, most standard backplane PCM data streams interface directly to the processor’s serial port(s), without any external hardware. This document provides schematics, layout suggestions, and a software framework for receiving, processing, and transmitting PCM streams between two T1/E1 transceivers/ framers. The chosen framing device