Connecting to POTS line

I’m looking into Asterisk to provide a PBX environment for a small home office. I’m by no means a linux sys-admin, but comfortable enough with linux to get Asterisk up and running. In almost other respects, I’m a complete newbie. I’ve been looking around, and it looks like Asterisk is exactly what I’m looking for, but I’ve been unable to find the information–or maybe I have, and just not comprehended it–on one thing.

Once I get the digital side of the equipment set up – the linux install, asterisk and all the phones configured, how to I hook that setup to the POTS line?

Like I said, I’m a complete newbie to VoIP applications, equipment and terminology. If someone could just point out “Here’s what you need n00b”, I’d appreciate it.


The “thingy” that you need is an ATA. Analog Telephone Adapter.

Digium makes a card that slots into the Asterisk server and is addressed natively. You can buy one here:

There are other devices you can buy. Sipura’s ATA’s come to mind as very good options if you are never going to go byond one or toe lines to the Asterisk box.

You can get those here: … cts_id=203


I’m in the exact same boat you are.

I think you want a card or device for FXO and FXS.

FXO is the connection from the telephone company to your asterisk box, which uses the standard RG11 cable/connection jack, and FXS is the connection from the Asterisk box to the plain old analogue telephone.

You don’t need any FXS if you are using VOIP phones. VOIP phones use standard ethernet.

I think I might get a TDM400P with 2 FXO and 2 FXS, or, perhaps 1 FXO and 3 FXS… The FXO and FXS for the TDM400P Digium cards seem to be little cards that fit on the TDM400p.

But I’m as new at this as your are, so be sure to check everything I said.

I want to get something to play with at this point, I may try to build a mini-PBX for VOIP using the mini-ITX motherboards which are 6 inches by 6 inches’ and can be configured for very low power consumption.

I’m not sure how far I will get though…

Randall Fox