[VoiceOps] AT&T Cellular - DTMF

Adam Vocks Adam.Vocks at cticomputers.com
Wed Jun 24 12:57:36 EDT 2015

I've got an odd problem that someone might be able to point me in the
right direction to get some help.


AT&T cellular customer calls a number destined to our LRN.  Customer
presses a digit on the phone, no DTMF audio ever comes across the trunk.
If that same customer calls a number with the same npa/nxx not destined
for our LRN, DTMF audio comes across the trunk.  These calls are coming
to us via SS7 trunks and the ILEC that these calls transit through has
verified that both calls come in on the same trunks, one has DTMF audio,
one does not.


This problem started on Thursday morning.  Prior to Thursday morning,
AT&T cellular calls were arriving to us via our FGD Tandem connection,
now they are arriving via the local rate center switch.


I've talked to AT&T and attempted to put in a ticket on the DS3 that
enters the ILEC, but they refused to do that because they said the DTMF
would be audio and they would just pass it through.


Anyone have advice?


AT&T (low level tech) states that the DTMF tones are generated at the
phone and are in the audio stream the entire way.  Does anyone know if
AT&T uses some sort out of band dtmf signaling?




Adam Vocks

CTI Fiber 

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