Synchronous Optical Network (SONET)
SONET is a clock-based frame transmission ANSI standard developed by Bellcore for digital transmission over fiber
Coding is NRZ data and an XOR with a 127 bit-long scrambling pattern to ensure a large number of transitions which can be used for clock recovery
Fixed frame time of 125 µs defines frame size for different clock rates, e.g. Synchronous Transport Signal STS-1 at 51.84 Mb/s = 810 Bytes long, STS-2 at 155.52 Mb/s = 2430 Bytes long and STS-48 at 2488.32 Mb/s = 38880 Bytes long
Concatenation of three STS-1 frames gives a STS-3c frame
Each column is a Byte wide so that a STS-1 frame is 9 X 90 = 810 Bytes
First two Bytes of each row is frame start delimiter