Special to Phone Watch

The open source Asterisk VoIP softswitch allows businesses to implement their own private branch exchanges (PBX) efficiently and cost effectively. Now Asterisk@Home lets home users have the same power and control over their VoIP telephone lines.

In this article I will outline setting up Asterisk@Home in a home setting, getting a VoIP telephone number, arranging for IAX PSTN origination and termination, and everything you need to set up truly do-it-yourself VoIP service.

Asterisk@Home is a pre-installed version of the Asterisk open source PBX. It comes on a bootable CD image which you can use to turn almost any old computer into a fully functional VoIP-capable telephone switch.

What you will need to make this work:

• An old computer. To serve a few phones in your home it preferably should be at least 500MHz, with at least 128MB of RAM and 2GB of hard drive space. All of the data on this hard drive will be erased! The computer also needs an Ethernet card to hook up to your broadband Internet connection and IP phones (see below).
• One or more IP telephones or SIP/IAX analog telephone adapters. If you want to replace all of your phones with IP phones, you can do so. Or you can use your existing phones and house wiring by obtaining an analog telephone adapter (ATA). You can also use an FXS card to connect your existing telephone handset directly to the computer.
• An account with an IAX VoIP provider which offers PSTN origination and termination service. This will provide your telephone number and let you make outgoing calls and receive incoming calls from the rest of the world. I’ll go into more detail below.

First off, obtain the Asterisk@Home software and install it on your old computer. Be sure to connect your computer to your broadband Internet connection. The handbook provides useful information you’ll need to set it up, but you don’t need to configure extensions, trunks, or routing yet.

Second, if you chose to replace all of your telephones with IP phones, you will then set up an extension in Asterisk@Home for each IP phone. Follow the directions included with the IP phone to configure it to speak to the Asterisk@Home switch. Once you have all of your IP phones properly set up, then each IP phone should be able to dial the extension of each other IP phone, and carry on conversations.

If you chose to use an analog telephone adapter (ATA) instead, you will need to configure the ATA to speak to Asterisk@Home, and configure the ATA as an extension in Asterisk, much the same as you would an IP phone. You must use an ATA which speaks either the SIP or IAX protocols. If you aren’t sure, don’t buy it. Follow the directions included with your specific ATA to set it up. Be sure to disconnect your house wiring from the (landline) telephone network interface (NID) on your house before you connect the ATA to your house wiring. You can easily do this by unplugging the test telephone jack in the NID.

If you want, you can also buy FXO cards, which let you connect your Asterisk@Home computer to a standard telephone line, and have Asterisk@Home serve that line, and FXS cards, which replace the ATA and serve a single (normal) telephone handset. If you’re running a business, you can also get a T1 card, which lets you run a T1 line (providing up to 24 phone lines) into your Asterisk@Home server.

Finally, you will need to obtain PSTN origination and termination services from a VoIP provider which uses the IAX protocol. IAX is a protocol used by Asterisk to speak to other softswitches, which passes easily through firewalls and home broadband routers. The SIP protocol, which is used by IP phones, does not easily pass through firewalls and home broadband routers, so it’s important that your service provider support IAX.

PSTN origination simply means a telephone call that originates on the public switched telephone network (PSTN), in other words, someone calling you. This provides you a telephone number where others can reach you. PSTN termination, on the other hand, means a telephone call that ends up on the PSTN, in other words, you calling someone else. You can order the services separately, but you will need both for complete telephone service.

You might want to order separate PSTN termination services for international calls, for instance, if a provider has cheaper international rates than your domestic PSTN termination provider. You can then have Asterisk@Home route domestic calls to the one provider, and international calls to the other provider. Your regular telephone just can’t do that, nor can the so-called VoIP services you buy in retail stores or from the large phone companies.

You can even order separate PSTN origination services. For instance, if you want a local telephone number in another country so people in that country can reach you, you can order PSTN origination service from a provider in that country which supports IAX call delivery, and people calling that number in-country will reach you for the cost of a local call. You pay only a minimal per-minute charge, or sometimes only a flat monthly charge.

There are a wide variety of Asterisk-compatible VoIP service providers out there now, so you will likely have to do some shopping. I got best results on Google searches for “IAX PSTN origination” and the like. Some offer extremely low per-minute rates and negligible monthly charges; others have somewhat higher monthly charges and free incoming minutes; others still have higher monthly charges and unlimited U.S. calling. Most even offer toll-free 800 numbers. Some will even let you get telephone numbers in other countries, which then route to your Asterisk@Home setup. Shopping for an IAX service provider will probably be the hardest part of this whole operation. Keep in mind that most IAX PSTN providers will not be able to port your existing telephone number; you will have to obtain a new telephone number.

Once you have selected an IAX VoIP service provider, the provider will give you the information you need to set up the trunk, outbound and inbound routing in Asterisk@Home. Enter this information into Asterisk@Home, and if all is well, you will be ready to go! Test your setup by dialing an outside number from one of your internal phones (your IP phone or your ATA-connected phone). Your call should go through. Then dial your newly assigned telephone number from an outside phone, such as your mobile phone. Your internal phone(s) should ring, and you should be able to talk.

Congratulations! You’ve just set up your own VoIP service, and the power behind Asterisk@Home lets you customize it far beyond what most telephone companies offer. For instance, instead of “call waiting,” where an incoming call interrupts your current call, you could have the second call wait on hold. Asterisk even lets you set up an MP3 playlist for hold music. It also includes this somewhat snarky message, use of which is optional:

“All representatives of the household are currently assisting other telemarketers. Please hold and your call will be answered in the order it was received.”

With most service providers, you can also, instead of having incoming calls interrupt you or be placed on hold, have those calls ring other extensions in your house. (But you need to use IP phones, or multiple ATAs, to set this up.)

This is only the beginning. Your voicemail service runs on your Asterisk@Home computer, and also provides a Web server from which you can access your voicemail, make changes, forward your messages to an email address, or many other functions. Or, just like your other phone company, just dial *98 to listen to your messages.

You can also set up conference calls. This is like three-way calling on steroids. You can add just about as many people as you want into the conference, and all of them can talk to each other on the same call.

In addition to the usual features like call waiting, call forwarding, voicemail, etc., Asterisk@Home also includes time, weather, and wake-up call services. It even can present callers with an interactive voice response (IVR) menu which you define.

When you get more into Asterisk, you can actually define your own services, to do just about anything you can imagine. Once you have Asterisk powering your telephone, the possibilities become endless. In a very real way, you are your own telephone company. And if you did your shopping right, you’ll be saving a bundle of money.