Technical Terms and Definitions

ESF - Telecommunications

Extended Superframe Format. A newer T-1 framing standard used in Wide Area Networks (WANs). With this format 24 frames of 192 bits each are grouped together with the 193rd bit providing timing and other functions. In this grouping, the 8,000 bps frame is redefined as follows :

  • 2,000 bps for framing and signaling to provide the functions generally defined in D4 the format.
  • 2,000 bps are CRC-6 (Cyclic Redundancy Check-code 6) to detect logic errors caused by line, equipment, noise, lighting and other interference. Performance checking is done by both the carrier and the customer without causing any interference with the T-1 traffic.
  • 4,000 bps are used as a Data Link. This link is used to perform such enhanced functions as end-to-end diagnostics, networking, reporting, and control, channel or equipment switching.