Editing Longitudinal redundancy check (section)

== Optimal rectangular code ==
While simple longitudinal [[parity bit|parity]] can only [[error detection|detect]] errors, it can be combined with additional error-control coding, such as a [[transverse redundancy check]] (TRC), to [[error correction|correct]] errors. The transverse redundancy check is stored on a dedicated "parity track".

Whenever any single-bit error occurs in a transmission block of data, such two-dimensional parity checking, or "two-coordinate parity checking",<ref>{{Cite web |url=http://personal.cityu.edu.hk/~dcykcho/dco2310/Chapter7.htm |title=Chapter1 |access-date=2012-08-20 |archive-date=2013-06-13 |archive-url=https://web.archive.org/web/20130613042831/http://personal.cityu.edu.hk/~dcykcho/dco2310/Chapter7.htm |url-status=dead }}</ref>
enables the receiver to use the TRC to detect which byte the error occurred in, and the LRC to detect exactly which track the error occurred in, to discover exactly which bit is in error, and then correct that bit by flipping it.<ref>
Gary H. Kemmetmueller.
[https://patents.google.com/patent/US4183463 "RAM error correction using two dimensional parity checking"].
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Oosterbaan.
[http://www.patentgenius.com/patent/4433388.html "Longitudinal parity"].
</ref><ref>
[https://web.archive.org/web/20190809065801/ftp://mail.im.tku.edu.tw/Prof_Liang/DataComunication&ComputerNetwork/5th%20Edi/Instructor's%20Manual_PDF/9781423903031_IM_PDF/9781423903031_IM_ch06.pdf "Errors, Error Detection, and Error Control"].
</ref>