Customer complains of callers not being able to dial touch tones via the auto attendant. Basically press 2 for appointments, 3 for billing etc. Works every time for me, I cannot duplicate it. I indicated cell phones may be the problem.

Customer is on Avaya IP office 8.1.(43) system with analog trunks via cable modem. Would I need to adjust something on the Trunk side? Or upgrade? System is otherwise working fine.