Optical Carrier transmission rates are a standardized set of specifications of transmission bandwidth for digital signals that can be carried on Synchronous Optical Networking (SONET) fiber optic networks.
Transmission rates are defined by rate of the bitstream of the digital signal and are designated by hyphenation of the acronym OC and an integer value of the multiple of the basic unit of rate, e.g., OC-48. The base unit is 51.84 Mbit/s. Thus, the speed of optical-carrier-classified lines labeled as OC-n is n × 51.84 Mbit/s.
Optical Carrier classifications are based on the abbreviation OC followed by a number specifying a multiple of 51.84 Mbit/s: n × 51.84 Mbit/s => OC-n. For example, an OC-3 transmission medium has 3 times the transmission capacity of OC-1.