SIP trunks to fax server works great but...

[jjenuine]

I have a working set of sip trunks used as a tie to our fax server and all traffic to and from the server uses our PRIs. We have 24 sip channels provisioned for the server, but just 12 fax server channels. Periodically through the week we get a rash of faxes to our switchboard when they have obviously faxed to the correct number. I suspect that when our fax server's channels are busy, the calls are being routed to the switchboard. I would like this to stop and, instead, give the calling fax a busy signal. I can't find anything that addresses how to change this and I'm hoping someone here will know.
This isn't a massive inconvenience but it does delay the fax delivery to the department and as a hospital that's not good.

 

[meneerB]

In general, you would configure a SIP trunk on the PABX for the connection to the fax server.
On that trunk you would limit the amount of channels used.
When you reach the 12 simultaneous call limit (which in my opinion is huge...), the PABX sends a busy to the caller.

On the fax server you should have configured the number of lines, according to your number of licenses on your faxserver.
These 2 should match (both 12).

To accommodate your customers, you should reserve a couple of lines for incoming faxes only (e.g. 30%), and use the rest for outgoing of bidirectional.
Configure that on your faxserver.

For your information:
We have 90 faxnumbers, 25k faxes (4 page average) outbound and 25k (2 page average) inbound a year with 6 fax lines.

 

[G van Hamburg]

How do you know they used the correct number? In system features there is an option to route ‘unused numbers’ to the the attendant. And since a fax tries several times, this could be the case. If you don’t know where to look in CM, just find an unused DID and call it. If the attendant takes the call and sees IC in the screen (intercept treatment) you know the issue.

Freelance Certified Avaya Aura Engineer

 

[jjenuine]

- Meneer - I'm going to change the number of channels on our SIP trunks to match what the fax-server has provisioned. They were initially both 24 but the project manager decided to not buy all 24 licenses, only 12. It didn't occur to me that the disparity would be an issue. I bet that's gonna be it.

We're pretty high volume: 70+ fax numbers and a small but growing number of desktop faxers. We average 16-17k in/out faxes per MONTH on that server and 12 ports is gonna give us some busy signals at peak hours.

- G van - Thanks for the thought, but I already have unused DIDs routed to dead-air, which has greatly reduced the amount of spam calls and faxes from being dumped on our switchboard! I can see the destination in the trace and they're valid faxes to fax numbers on our server.