I had a look at the URI parameter registry for SIP, it is at
Unlike with XMPP, there does not appear to be any parameter for
specifying the type of session to prefer with a URI (e.g. chat or voice
On the other hand, if I pass parameters like "?session-cookie=1234abcd"
then Jitsi happily passes these on to the SIP proxy when making a call
(with XMPP, it removes such parameters and shows an error popup).
The use case I'm thinking about is with java.awt.Desktop. If I create a
SIP URI and call desktop.browse(uri) then Jitsi always starts a phone
call and there seems to be no way to tell it to start SIP chat.
With XMPP URIs, then it appears to be the opposite, Jitsi starts an XMPP
chat and never a phone call.