[Asterisk-Users] Need Asterisk to generate ringing tone on inbound SIP calls

[Chris Joseph]

Hello

I have an SIP carrier defined on my Asterisk which delivers DID calls direct
to extensions. The extensions are all either SNOM 200's or Cisco 7905's
(SIP). The SIP carrier sends the extension number only in the invite, this
then rings the phone. Below is an ethereal trace of an inbound call from the
SIP carrier to extension 204 on *:

Source                Destination           Protocol Info
xxx.xxx.xxx.xxx       xx.xxx.xx.xx          SIP/SDP  Request: INVITE
sip:204 at xx.xxx.xx.xx, with session description
xx.xxx.xx.xx          xxx.xxx.xxx.xxx       SIP      Status: 100 Trying
xx.xxx.xx.xx          xxx.xxx.xxx.xxx       SIP      Status: 180 Ringing
xx.xxx.xx.xx          xxx.xxx.xxx.xxx       SIP/SDP  Status: 200 OK, with
session description
xxx.xxx.xxx.xxx       xx.xxx.xx.xx          SIP      Request: ACK
sip:204 at xx.xxx.xx.xx

The problem I have is that the SIP carrier is playing a non-UK ring tone
from a media gateway back in their network somewhere. They are playing
ringing because asterisk sends them a Status 180 and expects ringing to be
played at source. Since the call originates from the PSTN, "source" is
actually their media gateway where they meet the PSTN.

Callers are complaining as they are expecting to hear a UK ring tone since
they are calling us in the UK. I want to be able to configure asterisk to
play its own UK style ring tone, and to send a Status 183 instead of a
Status 180 back to the SIP carrier so that it opens the backward speech path
and lets the caller hear my UK ring tone.

The SIP carrier has confirmed that if a Status 183 is sent instead of a 180
they will allow the caller to hear whatever progress tone Asterisk plays.

I have trawled the WIKI, and drawn a blank. Can anyone please point me in
the right direction.

Many Thanks

Chris Joseph