RC5 uses a toggle bit. It changes one bit each time you depress the button. It should be expressed this way since the Pronto uses a special shorthand notation for RC5 since it is a Philips IR protocol. All are expressed in hex.
5000 0000 0000 0001 0010 0025
5000 means RC5
The first 0000 is a parameter N used to calculate IR carrier frequency and can either be 0000 because it is known or approximately 0073 (F (in KHz)=1000/(N(converted to decimal)*.241246)
The second 0000 is the number of pairs of one time data in this case none.
0001 is the number of pairs of repeat data.
0010 is the Group (or device code)=16 decimal for Amplifiers
0025 is the command =37 decimal that I believe will toggle through the surround sound mode.
Most Pronto's seem to be able to learn and recognize RC5 and translate to the format above. If not, it will not calculate the toggle bit which can cause problems. The toggle bit has to change in order for the device to see consecutive button pushes of the same command. For example if you wanted to switch to channel 111 then it would just see 1. 101 would work fine.
Having said all that, it is probably easier to find the commands by other means that you are looking for. What is the equipment and what commands do you need?
If you search the files section here under user documentation there is some information on the RC5 signals and how to decode. here is a link to one of them
[Link: hifi-remote.com]-Jon
This message was edited by jarmstrong on 11/16/02 09:05.42.