I have SIP trunked a ShoreTel system to a Mitel 3300mxe controller and things seem to be working great. DTMF tones work between the systems flawlessly. I can access auto attendants on both sides and key presses do what is expected of them.
However, when I try to call from the ShoreTel to a remote site using the Mitel T1s DTMF isn't passed through to the system that answers the call. This makes it impossible to call a site and enter an extension, use calling cards, flag VM messages as urgent etc.
Any assistance offered is greatly appreciated!