Serial Spy helps you to analyse serial protocols, you get a computer with two serial ports and run serial spy on it. You connect the device to one of the serial ports and the other to the computer you are running the program you wish to analyse to the other with a null modem cable. Serial spy collates bytes travelling in the same direction and logs lulls in the conversation by printing `.' .   Example output is below....

 . . . .
> 57
< 49
 . . . .
> 43
< 01 00 FF 50 49 43 30 30 30 31 2E 4A 50 47 00 30 30
< 30 30 30 30 34 32 37 37 00 00 00 00 00 00 00 00 00
< 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
< 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
< 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
< 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
< 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
< 00 00 00 00 00 00 00 00 00 00 00 00 7B 7D
> 06 43
 . .
> 06 43
< 02 01 FE FF
 . . . .

All you need to do is set the baud rate at the top of the source code spy.c and compile and run it. Each fullstop/period corresponds to a 1/2 second delay.

Have fun.