Spurious DTMF tones over calls.

[KeplerQ3]

Hi Forum I've recently bought a Obi202 with 1 Obiline to connect my Raspbx to my analogue line.
It works well and replaces my old SPA3102 which never worked consistently. I use a BT8500 Dect phone through a PAP2 to connect to the Raspberry Asterisk. I also have numerous SIP phones connected.

I have a problem where sometimes when on an external call all will be going well then suddenly I hear a loud DTMF tone drowning out the other party in the call. The tone lasts for approx 10 seconds then it goes away. Then another DTMF tone appears for about the same duration.

This only happens when the Obi202/Obiline is connected and on an external call. I hear it on all of the phones on the system but it doesn't seem to happen on every external call. It's fairly random.

I'm hoping somebody might be able to explain what's happening and hopefully provide a fix.

Many Thanks

[drgeoff]

Do you really mean DTMF (the DT means dual tone) or just a single tone?

And is the second tone the same frequency (or frequencies) or different?

[KeplerQ3]

Hi drgeoff yes I really mean dtmf, its just like someone's put their elbow on the dial pad. The subsequent tones are different frequencies. My ears are good but I cant detect which dial key sound is being transmitted.
I've been looking around the web somewhat and this isn't an unknown problem.

ref - https://www.ukvoipforums.com/viewtopic.php?f=10&t=725&sid=1be9abe6c2b6aca2378ea78b08a2c28d&start=15

It might actually be anything in my 'chain' (Raspbx, Obi202, Obiline, etc) but I've never experienced it till I recently connected the Obi202.

Try googling 'unwanted dtmf over call' and there's alot out there but few answers.

Cheers

[jc53593]

I am having the same problem.  My ObiLINE (attached to an Obi202) thinks it's detecting DTMF tones when there are none.  It's happening quite frequently with two specific female voices.  I saw this forum thread and several others describing this "talkoff" problem (what it's called, apparently) but no solutions offered so far, so I've opened a ticket with Obi support.

Has anyone found a solution that I'm just not seeing?

[Lavarock7]

Is this talkoff?


Talk-Off, or Talkoff, is the term that describes when a human voice is able to trigger touch tones, or DTMF tones during a telephone call. Talk-Off occurs when a signal processing system tries to translate sounds into to touch tones. Some people's voices are able to recreate touch tones frequently relative to the general population.

[atomski]

Same problem here and it's 2019 already.
Googled it, searched the forums, but didn't find anything that would fix this issue.

Anyone out there who knows how to deal with this?

Thanks!

[ProfTech]

I hate to say it, but this sounds like a problem with the Obiline adapter. Every one of these posts says they use the adapter. I bought one way back when but never used it. There have been several different issues reported with it. 

[jholme004]

I have an Obi212 - 1FXS; 1 FXO (ObiL:ine built in). I have the SAME ISSUE. Please post if you have any thoughts...