DTMF Out-of-Band to the PSTN

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Apr 20th, 2008
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I've been trying to figure out whether it's possible to configure on a Cisco Voice Gateway DTMF relay over SS7/ISUP. Let's say we've got the packet side with SIP dial peers, and they are generating DTMF, and using SIP Notify to send DTMF to the Voice Gateway, connecting them to the PSTN. Instead of playing DTMF inband, can the voice gateway use CED or some other SS7/ISDN means to relay DTMF to the remote end on the PSTN?




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dezoconnor Mon, 04/21/2008 - 09:22
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As far as I'm aware you can only configure either sip-notify or rtp-nte to relay dtmf. In the callmanager SRND guide look in Chapter 6 under Configuration of DTMF on SIP and H.323 gateways.


dobri Mon, 04/21/2008 - 13:58
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Thanks for the reply.

I am actually looking for DTMF relay on the PSTN side, rather than on the packet side (where CallManager, SIP and H.3232 reside). ISDN ISUP and other SS7 protocols support Caller Entered Digits (CED) and potentially other atributes that they can carry as part of ISUP and other SS7 signalling, rather than in-band. I am looking for a way to encapsulate packet side DTMF into ISUP or other ISDN messages on the PSTN.

Thanks anyway.


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