How to transfer custom data in a sip session?

Question

linux

There is information that anything can run inside the SIP protocol. RTP, for example.
It is necessary to transfer some user data via SIP, for example, the GPS coordinates of the device.
Can asterisk handle such custom data?
Or if you can, then you need to get such data from the SIP session in a java program or php script.
How can I do that?

Answer 1

SIP supports text messaging between clients.
Asterisk can send
such messages . Tell us the task in more detail.

Answer 2

SIPAddHeader(Header,Content)
SIP_HEADER()