Table of Contents
Advertisement
³
9
4
1
6
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
³
1
0
7
8
³
1
0
7
8
³
1
0
7
8
Block Check Character
³
1
4
1
4
³
1
4
1
4
Enable NCR Suffix Character
0
0
Enable Transmit of LRC Calculation – The
scanner outputs on LRC check character after
1
1
the bar code.
* Disable Transmit of LRC Calculation.
0
1
* Start LRC on First Byte – The scanner will
calculate the LRC check digit starting with the
0
0
first character.
Start LRC on Second Byte – The scanner will
calculate the LRC check digit starting with the
1
0
second character.
* Enable NCR BCC
0
0
Disable NCR BCC
1
0
8–7
Hide quick links:
Advertisement
Table of Contents
