The manufacture will not provide the information, so I am trying to reverse engineer the RS232 code/protocol. I have a windows program that communicates with an amplifier through a com port. Using a port monitor I obtained the following:
Send#Receive#Initial Volume#result volume
254 2 0 240 0 97 0 0 0 1 25 247 240 0 97 0 4 0 1 29 247#240 127 97 0 0 0 1 120 247 240 127 97 0 4 0 1 116 247#0#-0.1
254 2 0 240 0 97 0 0 0 2 28 247 240 0 97 0 4 0 2 32 247#240 127 97 0 0 0 2 117 247 240 127 97 0 4 0 2 113 247#-0.1#-0.2
254 2 0 240 0 97 0 0 0 3 27 247 240 0 97 0 4 0 3 31 247#240 127 97 0 0 0 3 118 247 240 127 97 0 4 0 3 114 247 #-0.2#-0.3
254 2 0 240 0 97 0 0 0 4 30 247 240 0 97 0 4 0 4 26 247#240 127 97 0 0 0 4 115 247 240 127 97 0 4 0 4 119 247#-0.3#-0.4
254 2 0 240 0 97 0 0 7 103 122 247 240 0 97 0 4 7 103 126 247#240 127 97 0 0 7 103 23 247 240 127 97 0 4 7 103 19 247#-100#-99.9
254 2 0 240 0 97 0 0 7 102 121 247 240 0 97 0 4 7 102 125 247#240 127 97 0 0 7 102 24 247 240 127 97 0 4 7 102 20 247 #-99.9#-99.8

but I can't figure out what is going on.... I've used decimal vs. hex, because I thought it would be easier to read and I have delimited the results with # sign's...

hex will be easer.

hex will be easier.

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Maybe if you listed what product you need the codes for, someone on here probably has them.

Dynaudio AIR series speakers.

I only have a small amount of experience with RS232 (hence the request for help).  I have added color coding to how I think the requests break down:

Initialization string (FE 2 0).
a command (F0 0 61 0 0).
a VALUE for volume
a checksum.
a termination (F7).
a command (F0 0 61 0 4).
a VALUE for volume.
a checksum.
a termination (F7).

I can't figure out the relationship between the VALUE and actual volume. I also can't figure out how to compute the checksum. In the program volume goes between +12 and -100, so for me to figure it out I think I will need more values. I COULD BE COMPLETE WRONG ABOUT EVERYTHING....

My program was giving me bad data.  Below are the necessary commands, but I still can't calculate volume. I also tried sending one and can't get the protocol correct..

Well the negative numbers are pretty straight forward. Multiply column 'F' by 128 and add column 'G'. You get column 'J' shifted by a decimal point.

The positive numbers are equilivant to 128 - column 'G' shifted by a decimal. This is essentially 16384 (which is 128x128) minus 16256 (which is128x column 'F') minus 'G'

This makes the negative numbers make more sense since they are subtracted from a baseline instead of additive.

Wow! Thank you!!! I was considering giving up...

I have been unsuccessful sending a command. I hope it due to me incorrectly configuring the port. Is there a port monitor (or something else) that can tell me the configuration of an open port?

I've got the protocol figured out, but I missed that I still don't know how to compute column H. Any ideas??