Welch Allyn Scanteam 3700PDF, Technical Manual

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Programming the Scanner 4–13
Programming Steps
1. Scan the Enter label on the Prefix/Suffix menu page.
2. On Bar Code Chart I, scan Roman Numeral I.
3. On Bar Code Chart III, scan 8
7
0
3
4. On Bar Code Chart III, scan 02
5. On Bar Code Chart I, scan Roman Numeral II.
6. On Bar Code Chart III, scan 86.
7. On Bar Code Chart III, scan 03.
8. Scan the Exit label.
The data will be transmitted as [STX]data[LRC][ETX]. The host can Exclusive–OR
each character as it is received, including the STX, LRC, and ETX. If no communication
errors have occurred, the result will be zero.
What if the application required two or more suffix characters following the LRC? To
what value should the LRC character be initialized?
Example Application #2
Remaining Prefix
Characters LRC,CR,ETX Bar Code Message
Prefix Suffix
Since the [CR] and [ETX] characters are transmitted after the LRC, they are not
normally included in the LRC calculation. You can, however, compute the
Exclusive–OR of all characters that follow the LRC, and then initialize LRC to that value
as the first step in the prefix.
CR binary value = 00001101
ETX binary value= 00000011
XOR’ed = 00001110 (0E HEX)
The LRC value would be initialized to 0E [SO].
Data will be transmitted as [prefix]data[LRC][CR][ETX]
If the LRC is the last character of the suffix, then it is not necessary to initialize its value.