Asterisk/FastAgi and Payphones

I have an asterisk box with two Zaptel Cards in it. I also have an IVR running using asterisk-java with fastagi. Everything works perfectly with normal phones/cell phones etc. But once in a while dtmf digits seems to be dropping when the ivr is accessed from a payphone. I’ve looked around posts but haven’t found a good solution. Any help would be greatly appreciated. Thanks in advance.

dail slow and hold each press a little longer…

This system is used by technicians out in the field. I don’t think they’ll like that solution. I will let them know and see if this works. But I’m still open for suggestions. Thanks in advance.

try relaxdtmf option (i think that’s the one)? Increases DTMF detection at the risk of getting false detections… try ti