8–7
Longitudinal Redundancy Check
A Longitudinal Redundancy Check (LRC) is an error checking character that is
calculated across a sequence of data characters. It is determined by eXclusive
ORing (XOR) the characters to be checked, starting with an initial value of
00H.
The result, an “LRC byte” is then transmitted following the data stream and
used by the receiving computer to determine if the information was received
correctly. In the scanner’s case, XOR is performed prior to adding parity bits.
When the LRC is enabled, the scanner defaults to starting the LRC on the
second byte of information transmitted. Optionally, the calculation can start on
the first byte transmitted.
³
1
0
7
8
1
1
Enable Transmit of LRC Calculation
– The
scanner outputs on LRC check character after
the bar code.
³
1
0
7
8
0
1
* Disable Transmit of LRC Calculation.
³
1
0
7
8
0
0
* Start LRC on First Byte
– The scanner will
calculate the LRC check digit starting with the
first character
.
³
1
0
7
8
1
0
Start LRC on Second Byte
– The scanner will
calculate the LRC check digit starting with the
second character.
Block Check Character
³
1
4
1
4
0
0
* Enable NCR BCC
³
1
4
1
4
1
0
Disable NCR BCC
Summary of Contents for GS220
Page 1: ...Configuration Guide GS220 ...
Page 23: ...3 6 ...
Page 31: ...6 2 ...
Page 57: ...9 6 ...
Page 63: ...10 6 ...
Page 73: ...12 2 ...
Page 77: ...14 2 ...
