Microsoft KB Archive/52196

= Serial Communications Parity Definition =

Article ID: 52196

Article Last Modified on 11/16/2006

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APPLIES TO


 * Microsoft MS-DOS 3.1
 * Microsoft MS-DOS 3.2 Standard Edition
 * Microsoft MS-DOS 3.21 Standard Edition
 * Microsoft MS-DOS 3.3 Standard Edition
 * Microsoft MS-DOS 3.3a
 * Microsoft MS-DOS 4.0 Standard Edition
 * Microsoft MS-DOS 4.01 Standard Edition
 * Microsoft MS-DOS 5.0 Standard Edition
 * Microsoft MS-DOS 5.0a
 * Microsoft MS-DOS 6.0 Standard Edition
 * Microsoft MS-DOS 6.2 Standard Edition
 * Microsoft MS-DOS 6.21 Standard Edition
 * Microsoft MS-DOS 6.22 Standard Edition

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This article was previously published under Q52196



SUMMARY
In serial communications, the parity bit is used in a simple error detection algorithm. As a stream of data bits is formed, an extra bit, called the parity bit, is added. This bit is set on (1) or off (0), depending on the serial communications parameters set in the UART chip. The following table lists the available parity parameters and their meanings:   Parameter  Meaning - ---

ODD       Parity bit set so that there is an odd number of 1 bits EVEN      Parity bit set so that there is an even number of 1 bits NONE      Parity bit is ignored, value is indeterminate MARK      Parity bit is ALWAYS set to 1 SPACE     Parity bit is ALWAYS set to 0



MORE INFORMATION
For the ASCII characters &quot;G&quot; (0x47) and &quot;I&quot; (0x049), the binary equivalents are 00100111 and 00101001. The following table is an example of how a parity bit would be coded for these values (the last bit is used as the parity bit):              G             I   ODD   - 001001111     001010010 EVEN - 001001110     001010011 NONE - 00100111? 00101001?  MARK  - 001001111     001010011 SPACE - 001001110    001010010

Additional query words: 6.22 3.20 3.21 3.30 3.30a 4.00 4.01 5.00 5.00a 6.00 6.20

Keywords: KB52196

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