[plug] OT: Data check digits

[Adam Davin]

Good Evening all, 

This is slightly off topic.

I am embarking on a learning journey to write a program that will take the place of a PDT (portable data terminal) the software on the PDT is proprietary and source is not available to me. What I have been able to do is borrow one of the PDT's and take a look at the serial communication between the PDT and the destination program using snooper. Below is a sample output. I can deal with most of it. The bit I am having problems with at present is the last 2(?) bytes on each line. I realise that these are check digits of some sort, I'm just not sure where to start in going about figuring out how they are calculated. 
Below is a sample. If more samples are required, I can get some more. 
0>1: \x05
1>0: \x06
0>1: \x01BHTQTYS.DAT 00003051304080808\x035
1>0: \x06
0>1: \x020000193117420003800005                        \x03\x07
1>0: \x06
0>1: \x0200002742709112010 0003                        \x03\x1e
1>0: \x06
0>1: \x0200003637407193402 0015                        \x03\x18
1>0: \x06
0>1: \x04
1>0: \x06

Any help would be greatly appreciated. 

Thanks in advance. 

Regards, 

Adam Davin.