Early RTP Inband Ringing Progress - chan-sccp/chan-sccp GitHub Wiki

Please use the default value for earlyrtp in your sccp.conf

sccp.conf

earlyrtp=progres

You can remove the entry completely and thereby get the default value (whilst shorting your sccp.conf).

Your dialplan Dial() command could look something like:

Dial(SCCP/1234, 60, R);
Dial(PJSIP/1234, 60, R);

From the moment you finished dialing the extension number you want to reach, chan-sccp will switch from the simulated dialtone to a simulated ringing tone. When the dial command is reached in the dialplan, the Dial Function takes over and will try to reach the destination. The destination will signal, that it is making progress towards the final destination, and potentially produce inband audio. For example it could announce that this call will cost xxx cents per minute. When the progress indication is received by the Dial() command, it will be passed along to chan-sccp, which will switch to inband audio using earlyrtp and open the rtp receive channel on the phone.

When using the Dial command, you can include the 'R' flag:

R - Default: Indicate ringing to the calling party, even if the called party isn't actually ringing. Allow interruption of the ringback if early media is received on the channel.

But do not include the 'r' flag:

r( tone ) - Default: Indicate ringing to the calling party, even if the called party isn't actually ringing. Pass no audio to the calling party until the called channel has answered. tone - Indicate progress to calling party. Send audio 'tone' from the indications.conf tonezone currently in use.

Note: Including the 'r' flag will prevent inband audio during progress, causing no simulated or real ringing to be heard.