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Does Callcentric support DTMF?
Yes Callcentric does support DTMF.

We support both In-Band DTMF and Out of Band signaling through the industry standard RFC2833 specification.

We recommend sending DTMF through the RFC2833 standard since it provides a more reliable way of transmitting DTMF signals compared to In-Band where compression, especially with highly compressed codecs such as G.729, in combination with poor connection quality can distort DTMF signals and make them unrecognizable.

If you choose to use the In-Band DTMF signaling method and experience problems with sending DTMF tones you can try to solve this by choosing G.711 as your preferred/default codec. This way your signals will be sent but won't be as compressed as when they are sent with G.729, or more highly compressed codecs.

If you are not able to choose RFC2833 standard as your DTMF type in your device, you may also be able to select AVT which is the name used for RFC2833 on some devices. You may also try setting your DTMF signaling type to Auto; this will allow your UA to choose the most suitable signaling type.

Callcentric does not support SIP-Info at this time as a method of transporting DTMF signals.

Here is a short list which explains Callcentric DTMF support for SIP communications:

1 - In-Band: Requires a stable connection and works best with a less compressed codec such as G.711. An unstable connection can still affect DTMF signaling however.
2 - RFC2833/Out of band: Works with any codec, as long as your connection does not suffer from high packet loss/ poor quality
3 - SIP-Info: Not supported at this time

If you still aren't able to send DTMF tones you may open a trouble ticket by logging into your account to contact us.