In modem settings switch to the scripting tab and where it says extra settings, type in the following to achieve the following:
01. M0 : switches modem volume off completely
02. &L=1,2, or 3 : changes the volume of the modem 3 being the loudest and 1 the quietest)
03. By experimenting with M0, M1,2 or 3 you are able to turn the modem on during connection only, ring only etc..