You can do this in several ways...I'm responding here as its SIP related, but we might want to a start a new topic to prevent cluttering this thread.
My focus here is for a working solution with Asterisk - note, Asterisk is not just a SIP proxy its a full PBX, it will handle TDM, SIP, SCCP, AIX and MGCP. Best way of running Asterisk for a novice is probably Asterisk@Home (its based on CentOs I believe). So it depends on what you want to do - see definition of FXO vs FXS.
1. Use an external ATA that converts POTS -> RJ45. Most of these are "locked" to a service provider such as Vonage. Some are available unlocked. They typically come with 2xFXS (provides dialtone versus FXO that expects a dialtone)
These products are aimed at plugging a convention phone into them and connecting direct to a VoIP service provider - in this case Asterisk (if the unit is unlocked)
2. If you simply want Asterisk to answer a POTS line, a TDM100P card (or clone) will do the trick. Its a glorified Intel V90 modem that acts as a single port FXO was was re-badged. Its no longer sold by Digium but range in price on eBay from $16-$30 depending on how "cloned" it is.
3. Preferred solution (also the most expensieve) is to use a TDM400P. You can then populate it with upto 4 x FXS or FXO modules to suite your needs. Expect to pay $140 - $350 depending on how many FXS/FXO's you add.
Originally Posted by Cynagen
Now that we have VoIP on our lovely little Wizards (aptly named I might add), is there any way to set up a SIP server say on a linux box that'll convert your home phone into VoIP? I know this is a little off-topic, but I work from home, and recently had to get a home-phone because I got charged with $800 in overages, so I'm hurting to find a way to null and void my cellphone's GSM link while in the house and have it use my home line for all my local calls, and keep my cell for long distance and just the random incoming call.