Just to let you guys know, I tested the following codes on a
Bell Mobility HTC Touch and they work
Just in case some of you lurkers are looking for what they can be used for, here you go:
##778# (EPST - you need to input your 6 digit MSL (get it using GetSPC.exe or BAFMSL.cab, as explained previously)) can be used to change the Slot Cycle Index, the frequency at which the phone sends out its info to the cell tower, which can be reduced for faster response upon ringing by the other party. Be aware that making the phone poll the tower frequently tends to deplete the battery dramatically, especially if you are far from the tower, which forces te phone to function at full power. You need to select "Modem Settings", the SCI is in there, most folks set it to 1 or 0 from the default 2.
##3424# is required prior to connect the phone to a USB port to work with QPST (which allows you to program the phone from the desktop and replace the OEM MSL code, among other things). You do need to have a proper driver package loaded on your computer. I needed the WModem Driver Installer, found somewhere else on this great site
##33283# is the Field Service Code, which is mainly used to asess Signal Strength in DBM, much more precise than any bar representations, great if you want to record how the radio version you have loaded performs compared to the one in the ROM you are about to load.
If some of these don't work, it's possible that the app the code starts is not actually loaded on your device.
Big Thanks to
stevopativo for finding and collating the codes