DTMF tones on Google Voice, Gizmo5, and SipSorcery

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What steps will reproduce the problem?
1. Create SipSorcery Account and place Gizmo5 and Google Voice Basic Dial 
account in.
2. Try to call 1-800 number that allows spelling on phone keypad or press key
3.

What is the expected output? What do you see instead?
For system to recognize input, ignores me.

What version of the product are you using? On what operating system?
Basic Dial Plan

Please provide any additional information below.

I have my system setup this way:

SipSorcery with Gizmo5 added as provider and Google Voice added with outbound 
dial plan and all works 100% for voice on iPhone using Softphone (literally 
called Softphone, not meaning it as a generic term).

Yet for some reason DTMF tones seem to fail, various 1-800 numbers completely 
ignore me when I press keys.

Yet when I used strictly Gizmo5 with GVOut on Windows, DTMF worked, so I don't 
think it's my iPhone setup.

Original issue reported on code.google.com by redpengu...@gmail.com on 20 Jul 2010 at 4:37

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[deleted comment]

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Update: For some reason this is working with Linphone on desktop, but it 
doesn't like Softphone on the iPhone nor SIP on my Nokia Internet Tablet N810, 
but currently it's the only well working softphone for me to use on iPhone and 
seems to be only SIP client for Nokia.

Original comment by redpengu...@gmail.com on 20 Jul 2010 at 4:55

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Sipsorcery and dialplan have no control over DTMF tones. DTMF tones can be 
passed by several different methods; typically SIP clients (ATA, softphone) 
provide with settings for it. You need to find compatible settings (read my 
comments to Issue 81).

Original comment by mte...@gmail.com on 20 Jul 2010 at 6:25

• Changed state: Duplicate
• Added labels: Type-Other
• Removed labels: Type-Defect

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Thank you so much, I read your comments, and they were helpful.

For some reason Softphone just says RFC 2833 (I know you mentioned that one) 
and SIP INFO (mentioned also) and simply "audio" which I guess must be inband.

For some reason nothing worked but "audio" but at least I finally got it 
working.

I know I don't use DTMF constantly but more and more places now of days seem to 
be going with it because of automated answering systems vs just a human 
operator.

Original comment by redpengu...@gmail.com on 20 Jul 2010 at 6:38

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In-band means that DTMF tones are transmitted as regular voice signal (in audio 
stream). RFC 2833 and INFO are "out-of-band" signalling methods; it means that 
DTMF tones are transmitted as SIP messages (separately from audio stream) from 
sender (your softphone) to the receiver (1-800 gateway) and then the receiver 
converts them into tones. In theory, out-of-band methods must be more reliable 
because they do not depend on audio quality, "stutter" and similar things. A 
long DTMF tone transmitted in-band may be interpreted as two digits if signal 
breaks due to the "stutter".

However, if RFC2833 and INFO are not supported in the receiver, in-band is your 
only choice. When it comes to 1-800 numbers, there are many SIP-to-Toll-free 
gateways to choose from. So, if it breaks again you may consider switching to 
some other gateway.

Original comment by mte...@gmail.com on 20 Jul 2010 at 7:01