telecommunications Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of ...

, a transverse redundancy check (TRC) or vertical redundancy check is a redundancy check for synchronized parallel

bit The bit is the most basic unit of information in computing and digital communication. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented as ...

s applied once per bit time, across the bit streams. This requires additional parallel channels for the check bit or bits. The term usually applies to a single

parity bit A parity bit, or check bit, is a bit added to a string of binary code. Parity bits are a simple form of error detecting code. Parity bits are generally applied to the smallest units of a communication protocol, typically 8-bit octets (bytes) ...

, although it could also be used to refer to a larger

Hamming code In computer science and telecommunications, Hamming codes are a family of linear error-correcting codes. Hamming codes can detect one-bit and two-bit errors, or correct one-bit errors without detection of uncorrected errors. By contrast, the ...

. The adjective "transverse" is most often used when it is used in combination with additional error control coding, such as a

longitudinal redundancy check In telecommunication, a longitudinal redundancy check (LRC), or horizontal redundancy check, is a form of redundancy check that is applied independently to each of a parallel group of bit streams. The data must be divided into transmission block ...

. Although parity alone can only detect and not correct errors, it can be part of a system for correcting errors. An example of a TRC is the parity written to the 9th track of a

9-track tape 9-track tape is a format for magnetic-tape data storage, introduced with the IBM System/360 in 1964. The wide magnetic tape media and reels have the same size as the earlier IBM 7-track format it replaced, but the new format has eight data ...

References

* {{FS1037C MS188 Error detection and correction