I have a pi running raspbx, and I have posted about this in raspbx, and done everything listsed there to ensure that this isn’t a raspbx issue. I am running freepbx Asterisk, it says “Ver. 11.17.0”. As far as I am aware everyihgt is up to date.
- UK landline coming into a Cisco SPA232D
- ‘hard’ phone on the other ‘side’ of the SPA232D
- softphones on various devices
I happen to have a loud ‘ringing device’ on the phone line before the SPA232D, it is a legacy device that means I can hear calls in the garden. Calls from softphone to softphone (or even soft phone to the ‘hard’ phone the other side of the 232) takes typically less than a second from dial to ring.
A note: As I am in the UK the sequence on the line is:
- Line reversal (which the ‘ringing device’ makes a ring ‘ding’ for)
- Caller ID information is transmitted.
- First ring.
However, incoming calls on the landline take a long time to ring, in the order of 3 and a half ringtones on the ringing device. I have watched the full log as it appears during a call. At the start of the first ring (ie after the line reversal and the CID information) it starts to log things. It is active for 2-3 seconds, about 1 of which is attributable to caller name look up. Then there is a long pause before the phones actually ring.
Now, I can reduce this delay by changing a setting on the spa232 but I am not sure if this is a good solution, and it raises a question about freepbx. What I did was to shortened SIP time T1 from 0.5s to 0.1s. As I understand it, this means the the SPA will take 0.1 seconds between the first invite to raspbx and the second one, rather than 0.5 seconds. The third will be after another 0.2 rather than 1.0 and so on, the gap doubling each time.
This suggests that asterisk/freepbx has a three step process here:
- Receive invite and do all the processing to be ready to invite the actual sip phones.
- Wait for the repeated invite to be sure it is a live call.
- Invite the sip phones.
Is this really the case? Is it possible to skip step 2?
Is this a sensible solution? What is the right way to speed up the ringing? It is such a long lag that it makes the system unusable for other users - they hear the first ring on the ringing device and then wonder why the phone isn’t working!