This article includes a list of references, but its sources remain unclear because it the scrambler method pdf insufficient inline citations. Please help to improve this article by introducing more precise citations. 66b is a line code that transforms 64-bit data to 66-bit line code to provide enough state changes to allow reasonable clock recovery and facilitate alignment of the data stream at the receiver.
It was defined by the IEEE 802. 3 working group as part of the IEEE 802.
The Protocol overhead of a coding scheme is the ratio of the number of added coding bits to the number of raw payload bits. 66b encoding is 2 overhead bits for every 64 raw bits transmitted or 3. 66b was deployed, it allowed 10 Gb Ethernet to be transmitted with the same lasers used by SONET OC-192, rather than requiring 12. 130b encoding, as used by PCIe 3.
132b encoding used by USB 3. As the scheme name suggests, 64 bits of data are transmitted as a 66-bit entity. The 66 bit entity is made by prefixing one of two possible two-bit preambles to the 64 bits to be transmitted.