Article View: comp.protocols.ibm
Article #485Re: LRC
From: Carlos Rimola
Date: Thu, 14 Jun 1990 17:45
Date: Thu, 14 Jun 1990 17:45
28 lines
1500 bytes
1500 bytes
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
Technical Details
Message-ID:
<1216@metaphor.Metaphor.COM>Path:
arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!brutus.cs.uiuc.edu!apple!metaphor!flamingo!rimolaReferences:
<9006111850.AA21192@lilac.berkeley.edu>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!brutus.cs.uiuc.edu!apple!metaphor!flamingo!rimola From: rimola@flamingo.metaphor.com (Carlos Rimola) Newsgroups: comp.protocols.ibm Subject: Re: LRC Message-ID: <1216@metaphor.Metaphor.COM> Date: 14 Jun 90 17:45:05 GMT References: <9006111850.AA21192@lilac.berkeley.edu> Sender: news@metaphor.Metaphor.COM Reply-To: rimola@flamingo.metaphor.com (Carlos Rimola) Organization: Metaphor Computer Systems, Mountain View, CA Lines: 28