A few years ago, I found a product that pretty much completed voice integration on my home Asterisk-based VoIP system.

As it was, I could accept calls over a variety of trunks and then route them around the house or to my office or soft-phone, or let them go to voicemail and wait for me or be sent to my e-mail inbox. And yet, I was still carrying around in my pocket an independent voice communications device: my cell phone.

When I thought about how I might like to integrate the cell phone, I came up with a simple goal: when I am at home, I want Asterisk to handle the cell phone like it handles any other trunk. When I leave the house, I want to be able to pick up the cell phone and walk away and have Asterisk still do the right thing (that is, not try to use it and fail).

My solution actually ended up being an analog solution: the XLink Bluetooth gateway. The XLink connects to up to three phones via Bluetooth and presents them on an FXO (line) port. The idea advertised on their web site is that you now hook up your home analog set(s) and use the cell phone like you use a landline. That’s OK, but is much more powerful if instead you connect this to an FXS analog telephony adapter for use on your VoIP system.

With this setup, you can treat the cell phone like an analog line in Asterisk, going through the ATA (I have the Cisco-Linksys-Sipura SPA3102). You can then set up an inbound route from the ATA–I just route it like any other call–and outbound routes–for example, for long distance calling, or 911.

What I like about this is that when I get home, I set my cell phone near the XLink (which happens to be in a convenient location) and then walk away. It connects by Bluetooth and now any calls I receive on the cell phone are presented to my home phones by Asterisk. When I’m ready to leave, I pick up the phone and go. The Bluetooth is disconnected and the XLink returns a reorder tone to the ATA if a call is attempted; the ATA understands the reorder tone and returns the proper failure code to Asterisk. In this way, Asterisk could even attempt routing to the cell phone when it is not there, and move on to the next possible route when the failure is detected.

The XLink really brings my home phone system together by including the cell phone without any additional work on my part except to take the phone out of my pocket when I come through the door.