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Avaya IPO 500 V2 SIP DTMF Tones Not Reliable

Avaya IPO 500 V2 SIP DTMF Tones Not Reliable

Avaya IPO 500 V2 SIP DTMF Tones Not Reliable

thread940-1768951: DTMF issue with SIP trunk
We have an Avaya IPO V2 Rev 9.0 system connected to ten Optimum (Altice) SIP trunks since 2014.
Right after installation, our installer went out of business, so I've been acting as the administrator since then.

Problem: After connection to the destination, we experience unreliable transmission of DTMF tones to enter PIN's, access codes, etc.
Some digits, on some phones, are sometimes not recognized - mostly just the digit "8" is affected. Other digits work fine.
Hanging up and redialing the number sometimes fixes the problem, but not always.

I just learned that Optimum requires Inband signalling for DTMF, since their VOIP network does not support out-of-band RFC2833 operation.
Since installation, IP Manager shows the original setting: Line | SIP Line 17 | VOIP | DTMF Support = "RFC2833".

Yesterday, I changed that setting from "RFC2833 to "Inband", hoping that would finally solve the problem.
The problem got marginally better, but is still there on some of our phone sets!

Optimum also advised me that many PBXs have default DTMF tone durations set too short for Optimum, maybe 100 - 200 msec.
Instead, Optimum requires that the DTMF tone durations are between 300 and 1100 msec. That seems VERY long to me!
I can't find any way to change the duration, and can't find out what the default duration is.
Does anybody know??

Lastly, I may need to access the Edgemarc interface, per the instructions from Optimum (attached).
I have not yet done so.

I would appreciate any insights and comments the Forum can provide!

RE: Avaya IPO 500 V2 SIP DTMF Tones Not Reliable

Set the codecs to the only supported one by your Sip provider in your Sip trunk. Check mark codec lock down and uncheck direct media.

RE: Avaya IPO 500 V2 SIP DTMF Tones Not Reliable

Dear icet500,

Thanks for your answer!

Here are the codecs we currently have enabled - the original "default" codecs since installation about 6 years ago:

G.711 ULAW 64K
G.711 ALAW 64K
G.729(a) 8K CS-ACELP
G.723.1 6K3 MP-MLQ

Are you suggesting that we should have only "one" of these enabled, or only the "ones" supported by our Optimum SIP service?

Thanks for any help on this!

RE: Avaya IPO 500 V2 SIP DTMF Tones Not Reliable

go to LINE>> SIP LINE >> VOIP >> "Codec selection" set to custom then select the only codecs supported by your SIP provider.

RE: Avaya IPO 500 V2 SIP DTMF Tones Not Reliable

Thanks, I have contacted the SIP provider to see which codecs are supported.

In the meantime, I did one more interesting test this afternoon.

I put two phone sets next to each other and used one to call the other.
After answering the called set, I pushed digits on the calling set, and listened to the tones on the called handset.

Sure enough, only the digit "8" DTMF tone is noticeably distorted compared to other the DTMF tones which sound reasonably clean.

That's the digit that we're have trouble with!!

Why and where would I go to fix that?

The DTMF audio tones must be generated in the IP 500 system because all of our phone sets are digital. Right?

RE: Avaya IPO 500 V2 SIP DTMF Tones Not Reliable

RFC2833 DTMF has a volume parameter. Maybe they're too loud?

Do you have a RTP capture of the RFC2833 DTMFs?

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