RoadRunners – Communication Protocol
TF -
Protocol of communication
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January 2007
6.4 Special command
Example 4.1 – Sending a special command to Code39 symbology.
We now want set a larger frame of Min-Max length for Code39 symbology.
Frame to be sent to the decoder:
‘E’
‘E’
3
‘C’ , 2 , 40
Header Type Size
Command
Reading this frame, the decoder understands:
The user wants to send a special command (Type "E") to Code39 symbology (Header "E").
The size must be at least 2 and the first byte of the command field must contain a code
(ACSII) that will tell (indirectly) the number of parameters following.
The command "C" will first read, it means “setting a Min. length and a Max. length”. Then
the usual commands ‘D’ and ‘e’ will be sent to enable Min length and Max. length for Code
39 symbology. Then the Min length will be set to 2 and the Max. length will be set to 40.
