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Barcode standard committees have defined whether presence of a check character is optional or mandatory.
|
Symbol Type |
Check Word |
|
EAN 13 |
Mandatory |
|
EAN 8 |
Mandatory |
|
UPCA |
Mandatory |
|
UPCE |
Mandatory |
|
CODE 39 |
Optional |
|
CODE 128 |
Mandatory |
|
Interleaved 2of5 |
Optional |
|
CODABAR |
Optional |
The ErrorCheck control effects only symbols that have optional Check Characters. The ErrorCheck control has no effect on symbols where the Check Character is mandatory.
The ErrorCheck directs the engine to verify the Check Character. If correct the engine will return a status of 0 and the Check Character is removed from the string. If incorrect the engine returns a 42 and appends the Check Character to the string.
Barcode symbols where the Check Word is mandatory behave as if the Error Check is always enabled.
Starting with version 4.52 of AX-4 a new control bit called AX_BAR_RETURNCHECK was introduced. If enabled this control forces the engine to always append the Check Character to the return string, regardless of barcode type. This is conditioned on the assumption that the printed symbol does contain a check character. The following two tables illustrate engine behavior as explained above.
Symbol types with Optional Check Characters:
|
|
Return status OK (0) |
Return status not OK (42) |
|
Check Character enabled |
Returns string |
Returns string +
check-character.* |
|
Check Character disabled |
Returns string +
check-character.* |
N/A |
|
AX_BAR_RETURNCHECK enabled |
Returns string +
check-character.* |
Returns string +
check-character.* |
|
* Provided the barcode symbol was printed with a check-character. |
Symbol types with Mandatory Check Characters:
|
|
Return status OK (0) |
Return status not OK (42) |
|
Check Character enabled |
Returns string |
Returns string +
check-character.* |
|
Check Character disabled |
Returns string |
Returns string +
check-character.* |
|
AX_BAR_RETURNCHECK enabled |
Returns string +
check-character.* |
Returns string +
check-character.* |
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* Provided the barcode symbol was printed with a check-character. |
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