[Asterisk-Users] Forwarded call flag

[Tom Samplonius]

On Tue, 8 Mar 2005 13:36:39 -0700, Dr. Matthew Roller
<matthewroller at gmail.com> wrote:
> When I forward my PSTN phone(Qwest) to my cellphone and someone calls
> it, my cellphone(AT&T) shows an arrow next to the caller id showing it
> is a forwarded call, is there any way to set that forward flag when
> forwarding a phone call through asterisk?

  It is possible using PRI signalling (ni2 for sure).  When running
q931 debugging on a PRI gateway, I can see that incoming calls that
have been forwarded actually have the redirecting number listed, and
the type of redirection (always, na/busy, etc).  I really doubt that
libpri has the capability to build these kinds of messages, let alone
an API to set the fields.  And then try to find a PRI provider won't
strip the messages (called GTD, if you talk to them).

  However, Cisco gateways running SIP can do this.  They are actually
able to set the redirecting number in the INVITE, and pass it to
another gateway, which can regenerate it back into a PRI message. 
Asterisk doesn't understand redirecting numbers in SIP INVITES though,
so this only works with gateway to gateway calls.

Tom