The concept of CRC-based framing was developed by StrataCom, Inc. in order to improve the efficiency of a pre-standard Asynchronous Transfer Mode (ATM) link protocol.
This technology was ultimately used in the principal link protocols of ATM itself and was one of the most significant developments of StrataCom.
The method of CRC-Based framing re-uses the header cyclic redundancy check (CRC), which is present in ATM and other similar protocols, to provide framing on the link with no additional overhead.
[clarification needed] For a tutorial and an example of computing the CRC see mathematics of cyclic redundancy checks.
The header CRC/HEC is needed for another purpose within an ATM system, to improve the robustness in cell delivery.
A hysteresis function is applied to keep the receiver in lock in the presence of a moderate error rate.
T1 is a time-division multiplexing (TDM) protocol with 24 byte payloads carried in a 193 bit frame.
This device found the 193 bit long TDM frame and put out the 24 bytes in a form that could be used effectively.
When it came time to produce a European product, the benefit of using 24 byte frames became a liability.