Today while doing a little support I had this strange issue: if a user dials out through a carrier, he/she will listen to the ringback tone right away; but if this same user calls to another extension he/she won't listen right away. Instead, you will have a variable dead air and then suddenly, the callee will answer.
When a caller listens to a ringback tone, it means that the callee has been reached and it has answered with a SIP signal. Usually, the normal SIP flow is as follows (it could vary):
Caller won't listen to the ringback tone until the callee answers with a SIP 1XX code and the switch forwards it. The reasons why this could happen are many. I can just think on the following (of course there are more):
Of course, there are more reasons. I think these are the most common. Fortunately for everyone, the FreeSWITCH has a way to workaround this issue. This means it will answer with the 1XX SIP code without waiting for the callee to answer. To do this you just need to set the following variable, just before the bridge statement:
That's it! Good Luck!blog comments powered by Disqus