We have iiNet Naked aDSL at home, using iiNet’s iiTalk VOIP service for our home phone (there is no PTSN).

Using the iiNet branded Belkin F1PI241EGau aDSL/VOIP router.

This setup works great, despite the Belkins bad (terrible?) reputation.

My housemate recently bought FAX machine, and has been using it through the iiNet VOIP line for a couple of weeks. It works great like that (with T.38), but it’s a pain having the FAX and voice phone on the same incoming number, hahah.

Time for a 2nd VOIP ATA
The F1PI241EGau only supports 1 VOIP provider, so I needed a 2nd ATA.
I already had a spare F1PI241EGau (haha yes, yet another “crappy” Belkin), so I would use that as the 2nd ATA, which I’ll refer to as a the “FAX router” from now on :-)

First I set everything up physically; FAX router plugged in to power, ethernet into the aDSL router, and FAX plugged into the “Phone 1” port.

Next I configured the FAX router so it behaved nicely as a “client” of my existing aDSL router, doing this properly (by “tricking” the router to thinking it has a WAN connection) ensures that it can function as designed and do things correctly, like resolving DNS, Quality of service packet scheduling, etc.

Now with the FAX router on my LAN subnet, able to resolve DNS and connect to “the internet” via my aDSL router as a gateway, it’s ready to set up the VOIP stuff. Because I already have a VOIP registration using port 5060 (the iiNet iiTalk service), I need to use a different port for this registration; this ensures that incoming calls are routed to the correct ATA, and (in my opinion) it keeps things tidier, which is why I’ll change ALL the SIP ports, not only the listening port. So SIP Listen Port, Proxy Port and Registrar Port are all set to 5061.

Now the VOIP status shows as being successfully registered.

I can test the outgoing VOIP service by making a call from the fax, and yep it works fine.

Incoming will not work until port 5061 is forwarded to the FAX router. So I set a simple port forward rule on my aDSL router, to forward port 5061 to the FAX router.

And tadar, incoming VOIP calls (to the 2nd VOIP account) work now too :-) Woo.