Code 39, Code 39 on/off, Code 39 start / stop characters – GoDEX GS550 User Manual
Page 64: Code 39 check character

6 - 6
Code 39
< Default All Code 39 Settings >
Code 39 On/Off
* On
Code 39 Start / Stop Characters
Off
Start/Stop characters identify the leading and trailing ends of the bar code.
You may either transmit, or not transmit Start/Stop characters. Default =
Don’t Transmit.
Transmit
Code 39 Check Character
* Don’t Transmit
No Check Character indicates that the scanner reads and transmits bar
code data with or without a check character.
When Check Character is set to Validate, but
Don’t Transmit, the unit
only reads Code 39 bar codes printed with a check character, but will not
transmit the check character with the scanned data.