With the current prevalence of Skype, Vonage, and other peer-to-peer and Voice Over IP (VoIP) providers, it seems that everyone is talking to everyone else online. The major providers offer smooth user interfaces, easy setup, and an established support network. With providers like Skype, you are also immediately connected to an immense network of users you can speak to for free. For most users, this ease of adoption is exactly what they desire. However, for us hardcore geeks, the depth of features and ability to custom tailor our services are the desired traits. One tool that lets the consumer take total control of all their telecommunications systems is Asterisk.
If you are like me, you have a home phone that you never use. It sits there unattended while you carry your cellular phone to the ends of the world. Your home phone line connects to the public switched telephone network (PSTN) and may even have its own voicemail account you pay extra for. In addition to your home phone, you probably have a cell phone with its own voicemail and number and possibly an online phone number with a service such as Skype or Vonage. You might also have a fax machine connected to your line at home. How can you use all of these lines in a cohesive fashion? Asterisk is the answer.
Asterisk is an open source software package with the slogan ?The Open Source PBX.? Originally created by Digium founder Mark Spencer to host his company?s phone system, Asterisk has ballooned into the Swiss army knife of voice software. Its support for call routing and call planning makes it ideal for setting up home and office phone systems with extensions and intercom functionality. It can host voicemail, interactive menu systems, and more. It has a massive list of features that is too long to detail here. Today I am going to focus on using Asterisk to consolidate your voicemail, internet phone services, and general home phone usage. I am going to mainly focus on concepts and hardware needs rather than the actual technical details. Attempting to use Asterisk is not for the faint of heart and should be reserved for those with at least basic hardware skills and some programming experience.
The Asterisk server can be installed on any modern computer system, your old 600Mhz clunker, and even some internet routers. It currently installs on Linux, BSD derivatives, and even on Windows. It runs most efficiently on Linux and FreeBSD. For most home users, running Asterisk on an old machine with a free, open source operating system is the most cost effective and convenient option. After setting up your OS and installing the Asterisk server, you need to connect your phone systems to the box. Phone lines should be connected into the server via an external network adaptor or a card installed in the Asterisk server. Asterisk supports use of several major FXO and FXS cards to support connections to phone lines. As a quick guide, FXO connects to the phone jack in the wall and FXS attaches to a phone, fax, or modem. Phone-to-ethernet adaptors and FXO/FXS cards range from thirty dollars to several thousand dollars depending on features, support, and number of lines. Several basic 56K modems will also work. I would recommend buying the cloned X100P cards from an OEM provider such as Digit Networks. These adaptors can be had for anywhere from eight dollars to just over fifty dollars and are proven cards that work reliably.
After you successfully install and configure your home phone line adaptor, you can start setting up your VoIP connections to utilize your existing internet phone service. Asterisk supports all the major VoIP standards such as SIP, SCCP, H.323, and more. Asterisk can immediately connect to most major providers via one of these protocols. Some research into which protocol your provider supports will be required. If you are using Skype it will be necessary to purchase a software package or hardware adaptor to convert the proprietary Skype protocol to one of the open standards. Most of these solutions range from thirty to seventy dollars.
Once your different inbound service providers are connected and configured you can begin connecting your hard devices such as phones and fax machines to any FXS ports or adaptors you have available. Each of these devices should then be configured as a client on the Asterisk server. This is relatively straightforward and open to much customization. You are now ready to begin creating your calling plans and custom services.
One of my favorite tricks after I have all of this set up is to create my own voicemail system. Asterisk has automatic support for voicemail and many extensions to its functionality. It can send voicemails as MP3 attachments to your email, send you a text message on your cell phone, and even automatically call any line you want and playback the message once you answer. One of the most convenient things to do is to unify your various voicemail services onto your one Asterisk server. First call your home phone provider and make sure they disable their voicemail service. Second, on your cellular phone, reconfigure the voicemail number to point to the Asterisk server at home. Then call the cellular provider and ask them to disable their voicemail if you are unable to do it yourself. Once you have done this, you can configure your Asterisk server to forward all incoming calls on all incoming connections (including your internet phone) to the voicemail box after a certain number of rings. Now you have a personalized, unified voicemail service with no monthly fee.
Asterisk can also be configured to automatically ring all your other phones when one of the lines has an incoming call, so you never miss another call again. To handle your faxes, Asterisk has a fax server module available. You can have faxes routed to your home fax from any phone number you possess. With the built in conference calling functionality, you can link your phone accounts together and talk to multiple people at the same time on different services. If you know what your various calling rates are on different services it is possible to have your Asterisk server route calls over the least expensive provider for each call. With Asterisk your options are nearly limitless, provided you have the time and perseverance to make it work. If you are interested in what Asterisk can do for you, there is an established user community and many great sources of detailed setup information. For more information, visit the Asterisk website at www.asterisk.org. A great public wiki with information on VoIP and Asterisk is located at www.voip-info.org. Happy talking!