[Blink] Inband DTMF

Adrian Georgescu ag at ag-projects.com
Thu Dec 3 19:22:44 CET 2009

Hi Willi,

Inband DTMF has been deprecated long time ago. The agreed standard for  
sending DTMF is RFC 2833 and Blink supports this method. I know that  
there is lot of legacy PBX out there still doing SIP INFO and inband  
DTMF but there is little we can do about this.

Even if Blink would support multiple types of DTMF sending, which will  
most likely won't because of the intrinsic technical hurdles involved,  
to support legacy devices you would still face the issue that it  
cannot be negotiated before hand so you must manually set the client  
every time differently. What works with legacy vendor A will not work  
with legacy vendor B. The last RFC is the answer and everyone need to  
upgrade their product to support it sooner or later.


On Dec 2, 2009, at 4:38 PM, Wilhelm Wimmreuter wrote:

> Hmm,
> is there a possibility to send inband DTMF with blink?
> Just tried out a conference bridge and I failed?
> Willi
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