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New Member

LinkSys PAP2T: problem with sending fax

We got a LinkSys PAP2T to connect analog fax machines to our Cisco  CUCM 7.1.

In several forums and communities I found a lot of  information to configure the PAP2T. (Jitter, Codec, Passthrough Methode,  etc.)

But as in other threats I have the same problem with  sending faxes.

Receiving faxs works fine and sending to our  Ferrari Fax Server too. But sending faxes to other "real" fax machines  fails.

The receiving machine goes offhook and they try to connect  (you can hear the modem tones) but connection fails.

As I  said, the PAP2T is connected to our Cisco CUCM as a SIP client. The  connection to the outer world goes via a Cisco 2821 router as a voice  gateway. The Ferrari Fax Server is connectet to our old PBX in the same  manner as our old fax machines, and the PBX is connected to the 2821  gateway. So the connection to the fax server is the same as to our fax  machines.

I tried with g711alaw and g711ulaw but send to  fax machines doesn't work.

I the dial-peer in the gateway I set  codec an fax pass-through to the same codec as in the PAP2T.

Can  anbody tell me what I can configure to make sending faxes work?


New Member

Re: LinkSys PAP2T: problem with sending fax

Dear Holger,

Not that I am very experienced with your exact setup, but I think there are at least two factors that affect FAX operation.

The first you have already ruled out, that is the use of High bandwidh codec, G711.

The second, which is likely the reason in your case, is to force your fax to a lower speed fax like 9600bps instead of the 19200bps.

I have noticed that many fax machines cannot handshake on 19200bps.

Good luck.


New Member

Re: LinkSys PAP2T: problem with sending fax

Sorry, but it don't work.

Lowering the speed to 9600bps (V.29) takes no effect.

I teted it with different machines.

I think I have to buy another ATA like the SPA2102 which supports T.38.