Monday, November 20, 2006

Planning the Asterisk Install

After reviewing the basic instructions found here, it would appear that I need to purchase PCI cards with Foreign eXchange Station (FXS) ports, and with Foreign Exchange Office ports. Telephones are connected to the FXS ports, and phone lines are connected to the FXO ports.

Apparently bad things happen if you get this wrong. FXS ports provide power and generate ring signals, while FXO ports receive power and ring signals. I'll have to be careful with that.

I'm also going to need an Analog Telephone Adaptor, or ATA, that acts as a gateway between my digital network (the Asterisk box) and plain old analog phones and phone lines. Fortunately, the most common ATAs offer FXS ports, so there is less hardware to buy (and money to spend).

Apparently there has been considerable success using the TDM400P with a couple of daughter cards for a self contained PC to handle everything. Or, we could go with the Sipura 3000 (a stand alone box that you connect your Asterisk machine to via ethernet). I guess it all comes down to price.

Pricing out the first option, the Digium TDM400P, doesn't look too bad. I found a decent price here, at

My, what a wonderful new crop of acronyms to learn. I connect from the CO to my FXO, then go through my ATA to FXS to connect to a phone and get dial tone. What fun.