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DTMF not working from Siemens C475SIP/C47H

martinhamilton
Dabbler
Posts: 12
Registered: 04-12-2008

DTMF not working from Siemens C475SIP/C47H

Can anyone help me.  My phone is working to the extent that I can make and receive calls fine and all that sort of good stuff.  Problem occurs when I dial into any system requiring dtmf signals (I hope I am using the correct terminology).  So if I have to enter a single number from the keypad, generally it is fine, but when I have to enter a squence I always get a response back saying the number i entered was invalid.  The recently one system read back the number I have entered, and for every number I pressed, they had recieved 2 numbers - e.g I entered 1234 but the signal received was 11223344.  I have contact Siemens and they said to resent the handset - didn't work and now they are saying the base station as well.  From memory however this has never worked and I have had 2 base stations (first one packed up), so I am reluctant to reset the base station cos of the hassle of re-inputting everything.
Has anyone else come across this, or might know what the problem is?  I be really grateful for any assistance.
cheers
martin
3 REPLIES
Community Veteran
Posts: 1,139
Thanks: 4
Registered: 20-07-2007

Re: DTMF not working from Siemens C475SIP/C47H

Hi Martin
I seem to recall having had a problem with DTMF some time ago although I don't think it was the same as yours.
The only thing I can suggest is making sure that the "RFC 2833" setting is ticked in Telephony>Advanced Settings (see screenshot). I think that's what I did to get mine working.
Bob
Community Veteran
Posts: 6,253
Thanks: 430
Fixes: 39
Registered: 30-07-2007

Re: DTMF not working from Siemens C475SIP/C47H

Martin,
Hi , I think Bob's on the right track there. It probably is to do with the settings for 'DTMF over voip settings'. Gradwell suggest RFC 2833 and Audio are checked  as indicated here http://www.gradwell.net/support/howto/article/410
This here http://www.fonosip.com/english/siemens-gigaset.html for another provider suggests RFC 8233  only for the S450/S685 ( same platform/firmware as the C475 ).
My guess is that you want RFC8233 only as Bob suggests but I'd try with various combinations if possible to see which works best.
martinhamilton
Dabbler
Posts: 12
Registered: 04-12-2008

Re: DTMF not working from Siemens C475SIP/C47H

Smiley thanks guys,  removing the codex seems to have done the trick.  So simple, but Siemens couldn't help!