Can INVITE support arguments (rfc4715)?

Is there a way to add additional arguments into INVITE request and header lines?

From RFC 4715:

INVITE tel:+17005554141;isub=12345;isub-encoding=nsap-ia5 SIP/2.0
To: <tel:+17005554141;isub=12345;isub-encoding=nsap-ia5>
From: "Bob"<>;tag=1928301774

I’ve got a clue regarding the INVITE line… $SIP_URI_OPTIONS.

But what about adding arguments to From and To headers, any idea?

A listing of SIP channel variables is contained here: … +Variables

Malcolm, tnx for your reply!

What I want to achieve is add an argument into the From header so:


I considered SIPAddHeader(From…) but I then get multiple headers as expected.

Can this be done in Asterisk?

I can’t think of a way to pull items out of the From header, no.

Ok, I’ve added the functionality I needed into the chan_sip, so in the dialplan it can be called like this:

And the result is an INVITE with;

Works same as SIP_URI_OPTIONS.

If anybody needs this, give me a shout and I’ll post it…

To get a feature added, implement it against the SVN trunk version, sign the electronic licence grant on and submit it as unified diff as an attachment to a new issue (tick the code or documentation box).

I know this is old.
Did this ever get posted to or to

Alec Davis