Fax Detection Fax Calls Ring Phones Once


UCM6202 V1.5B

I have one SIP connection with 5 DIDs (numbers) in it. One of the DIDs is the customers fax number. The default inbound route sends all calls to a ring group with all the telephones in it.

I have fax detection setup, fax intelligent routing to the FXS station that the fax machine is connected to. The fax machine is not in the ring group.

It does work, fax calls to the fax number do get routed to the fax machine ok, however, everytime a fax call comes in, it rings all the phones in the ring group once.

Is there a way to prevent this one ring on the telephones??

Thank you


Remove the fax number from the default route.
Create a second route with just the fax number. Direct the route to the fax extension.


The other alternative is to set up an IVR, set all calls to route to it and have fax detection turned on for the IVR…

When a fax comes in on any number it will be forwarded to the fax machine by intelligent routing


If the fax number is dedicated to the fax machine, then as costwisewpg has indicated, simply create the route that will send the call to the FXS (FAX) when the fax DID is dialed. You do not need the intelligent routing as you can set the FXS extension to be a fax gateway (in extension settings).

The issue was that the system did/does not know the call to be a fax call. It sees the call come in and initially treats it as a voice call; hence the ring in the ring group. Only when the system determines it is a fax does it now know and can then intelligently route to the FXS.

Scottsip’s suggestion is also valid. He method uses a screening IVR to answer the call first whereupon the system can detect and manage via the intelligent routing aspect. This prevents the ring group from seeing the call first as the system will have already handled it. This would be the solution I would use if I did not have a dedicated line for faxing.


Thanks all…my issue is that the SIP provider has one set of registration credentials for the group of 5 trunks (4- voice and 1- fax) so I can only register the whole group in the UCM.

I think I’ll get the fax line split out of the trunk group so it has its own set of registration creds, that way I can register it separately to the UCM, separate trunk and route directly to the fax FXS.

Thank you for your suggestions.



That is not necessary. You register under VoIP trunk.

You control the DID’s under inbound route.

You can have many DID’s on one trunk and setup an individual inbound route per DID.


What I’m suggesting is not a trick, or alternative way to make things work. Unless I’ve really missed some point you’ve made (always possible) what I’m suggesting is the common way this is supposed to work.


costwisewpg is correct. No real need, unless you prefer it that way .