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Outbound calls - DTMF issue

azgenus
Occasional Visitor

Outbound calls - DTMF issue

We have an NBX100/V3000 and recently changed ISP service to a dynamic T1. After the change, we are no longer able to access third party conference bridges for a client.



When calling the external conference bridge number, we are asked to enter an access code. When we enter this code, it is not properly deciphered by the conference system, and we are not able to access the call. The issue looks to be an incompatibility with DTMF (this has been confirmed by both the conference host and our ISP). The DTMF tones are not being recognized by the destination system.



Is there any setting we can change on our end that might help resolve this issue? I see there is an "RTP DTMF Payload Type" parameter (set to the default of 97); will changing this value provide any benefit?



I'm not very advanced with NBX configuration/administration, so my apologies if I've left out any necessary info. Any assistance is appreciated.



4 REPLIES
bosoxfan_1
Super Advisor

Re: Outbound calls - DTMF issue

The RTP DTMF payload type is only used when running in SIP mode.. are you in SIP Mode?



if so, you could try changing it to 96 and see if that works.



 



How is the call going out? when you dial the conference bridge, what number are you dialing? Not sure if



the T1 you refer to is a SIP T1 or "raw-bit" T1 (from the PSTN)



merlin_1
Super Advisor

Re: Outbound calls - DTMF issue

Also what type of device are you dialing out from ?



Analog / digital tel ?



Digits are out of band signaling passed from device to device , so tones should be heard over the line .



You should call a telephone ( anyone )  over the T1 and dial digits after you answer the call and see if You can hear them on both ends



azgenus
Occasional Visitor

Re: Outbound calls - DTMF issue

We are not in SIP mode, go I guess changing that won't have an effect.



The initial call is made to an 800 number, and then we are prompted to enter the bridge code. The call goes out fine, but it is at this point of entering the code that the destination system does not understand the digits we dial.



We are calling from digital phones (3Com 3102B), but I've tried it from an analog phone connected to our analog terminal card, and the same issue exists. When I call my cell phone from our phones, I can hear the digits when I press them.



The underlying issue is that the destination conference company does not work with some VoIP systems (as stated in their troubleshooting page). I am just wondering if there is anything we can do on our end to get it working.



merlin_1
Super Advisor

Re: Outbound calls - DTMF issue

VOIP IVR should be no different from a standard Telco IVR as the DTMF played should be understood the same way on telco lines . DTMF tones are frequency related and All systems rely on the digits to be played just like an Avaya or an NBX . I would contact the Company that makes the equipment and ask if they can listen to the tones coming in .  seems like the digits are played but the may be not sensative enough to be heard by the IVR system .