SDLC Interface Adapter in Microprocessor-Based Modems
Original Publication Date: 1985-Nov-01
Included in the Prior Art Database: 2005-Feb-19
Modern modems are generally built around a microprocessor which carries out most of the signal processing tasks required for modem operation. In those modems which must be capable to intercept SDLC (synchronous data link control) or high-level data link control (HDLC)-like frames, means must be provided to handle those operations that are required for SDLC protocol, including flag detection, zero bit insertion and deletion, and frame check sequence (FCS) generation and checking. This article describes a technique which provides SDLC protocol handling in an hardware interface which frees the microprocessor from these tasks, thus saving computing power and ROS (read-only store) occupancy in the microprocessor.