Pbx not hearing dtmf tones

Hi, I have a problem where I can establish an external call but am unable to utilise any features like call transfer etc. I cannot use the star codes to access voicemail either.

I can hear the tones being generated but it seems they’re not heard by the pbx. The dtmf tones sound very ‘dirty’.

I’ve even tried using an external tone generator to see if that resolves things but it doesn’t.

I’d heard that adding an extra chanel just for the dtmf resolves this but don’t know if it does or how to do it.

Are you sure your phone is passing the proper tones? For example, the Grandstream phones require in the phone settings menu for the ‘send DTMF’ to usually be set at via RTP (RFC2833). Change your setting and see if that doesn’t cure your problem but be sure to save the setting and reboot the phone for it to take effect.

Hi joeyga, the pbx is set up for rfc2833 and the phones are also set the same. As mentioned, I’ve even tried a dtmf generator with no effect. The same happens with a softphone so it’s nothing to do with the phone generating the wrong tone as it’s been totally removed from the equation.

Up until today my DTMF was working fine. I haven’t changed anything except redirect my fax to a different ZAP extension (moved the machine to a different location). Suddenly today my two Aastra 57i phones are not passing the tones to the PBX. Incoming calls work fine. Just internal calls have no DTMF. For instance I dial *98 to get into the voicemail system. When it asks for the mail box I enter the number, but no numbers are received by the PBX. Same if I dial 7777 to simulate a call… when I press 1 one for sales, but nothing happens. While watching the Asterisk CLI it does not show any DTMF input.

I changed my fax back to the way it was but no effect. I restarted AMP and the system with no luck. Any ideas?

Hi gicandles. You can get further than me as I can’t even access voicemail or any features of the system.