Q

How do you divide DTMF transmissions?

How do you divide DTMF transmissions?

How do you divide DTMF transmissions, such as in-band or out-of-band? Can RFC2833 be considered in-band?
In-band DTMF specifically refers to sending the DTMF digit frequencies along the same voice path as the actual speech in a conversation. This works well for an uncompressed channel using G.711, but does not work reliably when using a compressed channel such as G.729.

RFC2833 DTMF uses an out-of-band approach. The idea here is that special Real-Time Transport Protocol (RTP) even messages are sent instead of the raw tones. For example, a message is sent indicating a "DTMF digit 7" versus sending the two frequencies that make up a DTMF 7. This approach is more reliable.

This was first published in March 2006

Dig deeper on VoIP Migration and Implementation

Pro+

Features

Enjoy the benefits of Pro+ membership, learn more and join.

Have a question for an expert?

Please add a title for your question

Get answers from a TechTarget expert on whatever's puzzling you.

You will be able to add details on the next page.

0 comments

Oldest 

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to:

-ADS BY GOOGLE

SearchMobileComputing

SearchNetworking

SearchTelecom

SearchITChannel

SearchEnterpriseWAN

SearchExchange

Close