Hi all, I might be loosing the plot but I cannot get DTMF tones to transfer from a cell phone to the 3cx system when it rings simultaneously as part of the extension. For example, Door entry system rings extension 300, this rings mobile as well as the extension. If you pick up the call on the mobile, audio is fine but DTMF tones do not seem to work. Although they look to be transmitting. Works fine on Avaya system with same entry unit and sip trunks. Entry unit is a 2n IP Base. All DTMF tone tone options are open for incoming traffic. I have tried the 3cx on all variables of codec and DTMF and am at a bit of a loss. Anyone got any ideas?