Recently we needed to formally integrate a fax machine into our Trixbox / Asterisk office phone system.  In the past we just had a simple phone splitter and hoped the line wasn’t in use.  We have grown to 15 people in our office, so yelling “Is everyone off the phone lines?” is a bit disruptive to our office staff.

The first step was to research a solution, and a Cisco Linksys PAP2T device seemed like the best device.  Usually it is bundled with a service contract by VOIP Internet phone companies, and there are many unlocked units available ($32 incl. shipping – I love eBay).

Once the device arrived, I first created a SIP (Session Initiation Protocol) extension in our Trixbox configuration panel (we used extension 40).

Next we need to know the IP number used by the PAP2T so we can use a web browser to program it to interface with our Trixbox phone server.  First plug in the power connector, an ethernet cable to a DHCP-enabled network, and an analog phone into line 1.  The analog phone should have a dial tone, so from this phone type four asterisks (“****”) to activate the PAP2T voice-based setup menu.  When prompted, type “110#” to get the IP number of the PAP2T.  Another way of determining the IP# is to

From a web browser, enter the IP# of the PAP2T device (our device used http://192.168.1.131).  You should next see the PAP2T configuration screen.  Click the Admin Login link at the top-right, then click the Line 1 tab.  These fields had to be entered:

• Proxy: 192.168.1.2 (use the IP# of your Trixbox server)
• Display name: fax
• User ID: 40 (this is the extension)
• Password: **** (no, I’m not going to reveal our password here!)

Different trixbox setups may require different configuration settings, but these four items were all that we needed.  Click the submit button any you’re ready for faxing.

Note that this is not the only way to integrate a PAP2T with Trixbox.  Other solutions used TFTP to program the PAP2T during a device restart, but this seemed unnecessary compared with the simplicity of the above instructions.  And there are plenty of software or service solutions (e.g. HylaFax, asterfax), but our fax machine is also an office scanner and copier so we wanted a hardware solution.

Someday we may add an automatic fax signal detector and route a fax automatically to our fax machine (it seems to be a simple Trixbox setting or extension), but that’s a future project.