Method for carrying DTMF by SIP info

Method for carrying DTMF by SIP info

Version 0.9 2009-9

 

The main source of this article is references [1].

 

I. Method:

1) DTMF-relay and Kapanga

-----------------------------------------------------------------

Info SIP: 7007471000@example.com Sip/2.0

Via: SIP/2.0/udp alice.uk.example.com: 5060

From: <SIP: 7007471234@alice.uk.example.com>; tag = d3f423d

To: <SIP: 7007471000@example.com>; tag = 8942

Call-ID: 312352 @ Myphone

CSeq: 5 info

Content-Length: 24

Content-Type: Application/DTMF-relay

Signal = 5

Duration= 160

 

 

2) DTMF, a rare method. For example, the following is an info message for transmitting dtmf5.

-----------------------------------------------------------------

Info SIP: 7007471000@example.com Sip/2.0

Via: SIP/2.0/udp alice.uk.example.com: 5060

From: <SIP: 7007471234@alice.uk.example.com>; tag = d3f423d

To: <SIP: 7007471000@example.com>; tag = 8942

Call-ID: 312352 @ Myphone

CSeq: 5 info

Content-Length: 1

Content-Type: Application/DTMF

5

 

 

Ii. Problems:

1. It seems that either of the two methods can carry only one DTMF button at a time?

2. In some implementations, DTMF "*" "#" directly uses the characters of these two keys instead of converting them into numbers (10 in rfc2833 indicates * 11 indicates #), is this universal? -- Kapanga is also represented by characters.

 

 

Iii. Others:

1. The corresponding RFC document is not found.

2. Use subscribe/notify to implement the DTMF Event Notification function. For more information, see [3.

3. The difference between info and consumer Y: info is initiated by the producer, and the receiver receives the key and obtains the key. Consumer y needs to subscribe first?

 

 

 

[1] http://www.voip-info.org/wiki/view/SIP+Info+DTMF

[2] Sip info Method for DTMF tone generation, http://www.cisco.com/en/US/docs/ios/12_2t/12_2t11/feature/guide/ftinfo.html#wp1024388

[3] DTMF events through sip signaling, http://www.cisco.com/en/US/docs/ios/12_2t/12_2t11/feature/guide/ftnotify.html#wp1024644

[4] Sip subscribe/notify Method for DTMF, http://www.dialogic.com/webhelp/IMG1010/10.5.0_WebHelp/WebHelp/Description/Interworking/SIP_Subscribe_NOTIFY.htm