How can I connect legacy telephones to my Asterisk box?

I’m a newbie but have Asterisk running on my Linux WRT54G router.

I’d like to connect my legacy telephones (eg. all the current telephones in my house) to my SIP server and I really don’t want to buy a dedicated SIP phone (I’d like to use my current phones). From what I’ve read I need a “Zaptel” interface card, but since I’m running Asterisk on my router I obviously can’t install any type of expansion cards…

Can I buy any “ATA” device and plug it into my current RJ-11 jacks to provide a dial-tone to the rest of my house?

From what I understand, that’s exactly how the sipX PBX works: If you want to have it support connections to the POTS, you have to plug in an FXO-SIP adapter to act as an interface between the POTS and the LAN. … 6_Gateways

Ok, so all I need is an “FXS” card? Would you recommend any for under $50? (for the best sound quality)

Also, can I plug in the phone cord from the FXS device into an RJ-11 jack to provide ALL analog jacks in my house with phone service?


Precisely, it’s not a card, it’s a stand-alone box with two plugs : one to connect it to the POTS line, and one to connect it to your LAN and speak SIP with the PBX (Asterisk, sipX, etc.)

Others here will chime in. If not, more info on hardware at

There are two types of widgets: One that speaks FXO-SIP (to connect your VoIP LAN to the POTS), and ATA connectors that speak FXS-SIP (to connect analog phones to an SIP LAN).

If you want to reuse all existing analog phones, each will have to be plugged into its own ATA widget. Considering the cost of IP phones, it might make more sense to buy IP phones directly.

Technically not true…It depends on how your house is wired, where/how you connect the PSTN & ATA Device, and what you want to do. In my case all my phone jacks are “Home Runs” (I.E. Every jack has a separate pair of wires to where the wires from the Telco come it.) I have set up Asterisk & an ATA both connected where the Telco comes in, * to the PSTN, all the other lines to the ATA…Now it works just like a regular connection (All the phones are on the same circuit and they all ring at the same time on the same line), just they now have access to VOIP Calls via the Internet. Now if you want all the Analog phones to act as separate phones/lines then you start running into issues about multiple ATA’s, multi-port PCI Cards (Like the Digium TDM4XXP, or TDM2400P) or new IP Phones.

You lost me :smile: If you have a diagram of how you set things up in your house, I’m interested.

i hate to be the bearer of bad new but you may run into a problem by hooking all of your phones into one ATA or even the TDM card made by digium. lets start off as if you only had one phone pluged into the ATA, that phone require a power source running through the ata. if you have too many phones pluged in at one time and more than that one phone is off hook then there will be too much power drained from the line. then all you will get is static through both phones due to the lack of sufficiant power. im still researching on a way to “inject” more power into the pots line if its even possible. please let us all know if you can get it to work.