glenn@welch.jhu.edu (Glenn M. Mason) (06/12/90)
Has anyone out there heard anything about Longitudinal Redundancy Check (LRC), ISO 1155? eAny descriptive info or info on how to calculate would be greatly appreciated. Thanks, Glenn Mason Internet: glenn@welch.jhu.edu
rimola@flamingo.metaphor.com (Carlos Rimola) (06/15/90)
In article <9006111850.AA21192@lilac.berkeley.edu> hank%bitnic.BITNET@lilac.berkeley.edu writes: >Has anyone out there heard anything about Longitudinal Redundancy Check >(LRC), ISO 1155? eAny descriptive info or info on how to calculate would >be greatly appreciated. > >Thanks, >Glenn Mason > >Internet: glenn@welch.jhu.edu LRC as used by IBM 270X and 370X Async/Bisync is simply an odd or even parity check performed accross a stream of bytes. The LRC check byte is transmitted following the end of transmission character (e.g. ETX). For example, transmitting the string "ABCD" would result in an LRC byte of B'00000100': A = B'01000001' B = B'01000010' C = B'01000011' D = B'01000100' --------------- LRC = B'00000100' The algorithm for calculating the LRC is simply to XOR each of the bytes in the input stream. The first XOR should be made against X'00' for even parity and X'FF' for odd parity. Carlos Rimola
rimola@flamingo.UUCP (Carlos Rimola) (06/15/90)
In article <9006111850.AA21192@lilac.berkeley.edu> hank%bitnic.BITNET@lilac.berkeley.edu writes: >Has anyone out there heard anything about Longitudinal Redundancy Check >(LRC), ISO 1155? eAny descriptive info or info on how to calculate would >be greatly appreciated. > >Thanks, >Glenn Mason > >Internet: glenn@welch.jhu.edu LRC as used by IBM 270X and 370X Async/Bisync is simply an odd or even parity check performed accross a stream of bytes. The LRC check byte is transmitted following the end of transmission character (e.g. ETX). For example, transmitting the string "ABCD" would result in an LRC byte of B'00000100': A = B'01000001' B = B'01000010' C = B'01000011' D = B'01000100' --------------- LRC = B'00000100' The algorithm for calculating the LRC is simply to XOR each of the bytes in the input stream. The first XOR should be made against X'00' for even parity and X'FF' for odd parity. Carlos Rimola