So we are testing an integration with a fax server from a voice gateway. We have an FXS/DID card in the voice gateway with lines connecting to the fax server (FXO I would assume). My understanding was that FXS ports could not send digits down to the FXO side. I then did some more research and remembered that you could use an FXS/DID card to pass digits, but that would require you to enable DID mode on the FXS ports because the default is FXS mode.
My problem is, we have not enabled DID mode and it appears that the FXS port is passing digits down to the fax server because the fax is getting to the right user on the fax server side. It's not REALLY a problem because it's working, but it contradicts the way I had always thought FXS worked and what I have read.
Any ideas on how the fax call is getting to the right fax server user when it is going from an FXS card on a Cisco voice gateway to the fax server?
We are using Loop Start signaling.
FXS can pass digits after the connection is done.
So FXS rings, fax sever answers, FXS sends some digits, and the fax goes where it's supposed to go.
How come in another post you make it sound like you can't? Or maybe it was for that scenario in the post.
Good point. Let's say, the system controlling the port may or may not be able to send digits after answer. In your case, it does
Are you referring to the system controlling the FXS port or the system controller the FXO? Is there any documentation that supports this? Everything I have read makes it sound like regular FXS ports cannot send digits. The only option that would allow that is enabling DID mode on an FXS/DID port.
The system controlling your FXS. There is nothing preventing an FXS ports to generate digits (a dsp function) after connect. You can try, e.g. from an IP phone.
Note, in DID mode, an FXS port receives digits from the C.O. That is not much different with receiving digits from a telephone set.
i had similar scenario. What was the verdict of this solution? where you able to send digits after you siezed the FXS line?
Yes, in this case we had an FXS port on our voice gateway with a line running from it to the fax server. Multiple dial-peers pointed to the FXS port for the range of fax numbers. The fax server was able to see the digits and send the fax on for whom it was for.
Just out of curiosity if you could post config from your fxs ports and dial peers to fax server
Sent from Cisco Technical Support iPad App
i had a VIC3-4FXS/DID card connected to PBX. I was able to send digits from router to PBX.
If its in hwic slot 1 then the first port config will be like this. station-id is used for inbound calls from PBX if PBX was not able to send caller ID. usually we wouldnt use by directional to avoid glare. Winkstart or delay or immediate start signaling would be used only if we use the FXS port in DID mode.
description Outbound FXS port to PBX
signal groundStart or loopstart
station-id number XYZXYZ
dial-peer voice 1000 pots
description Calls to PBX station 57XXX
progress_ind setup enable 3
progress_ind alert enable 8