Optical Carrier levels (OCx)

It is a standard for optical fiber data transmitting.

The base rate (OC-1)
The base rate (OC-1) is 51.84 Mbps.

OC memo
The Synchronous Optical Network (SONET) includes a set of signal rate multiples for transmitting digital signals on optical fiber.

Asynchronous transfer mode (ATM) makes use of some of the Optical Carrier levels.