Hi all, I have a customer with multiple UCX 250's R6 all updated, each with an Allstream SIP trunk. Recently they have received complaints that some callers can't navigate the IVR via touchtone. After some experimentation, we found that the problem only occurs when using ATT cell phones(all other carriers work fine). When a digit is pressed, the system doesn't respond as though anything was pressed. The same cell phone can call a different company (like a bank) and has no problem. These systems and the sip trunks have been in service for at least 2 years each and have only developed an issue in the last week. this doesn't feel like a problem with the Emetrotel UCX, but I would like to know if there are any tweaks I can make to affect what might be an issue outside the customer's relm.