“Clearly, the future of telephony is the Internet, for which geographic location and distance don’t matter.”
Andrew Sheppard
Voice over Internet Protocol (VoIP) enables you to use the Internet for making phone calls. Calls from one VoIP phone to another are free and long-distance calls to a landline can typically be made for the price of a local call. VoIP also enables you to receive calls anywhere you connect to the Internet.
What Do You Need?
VoIP telephony requires reliable broadband connection to the Internet with a speed of at least 128 Kbps in the upload direction. In addition, there are three different types of hardware to chose from:
1) Peripherals, such as USB handsets, are relatively cheap to buy and plug straight into your computer. Used in conjunction with suitable software, they instantly turn your computer into a VoIP telephone. The most obvious drawback to such a solution is that your computer needs to be switched on to receive incoming calls.
2) Dedicated IP telephones are generally more expensive and function as independent devices on the network. However, setting up an IP telephone behind a router/firewall with Network Address Translation (NAT) can present you with additional configuration challenges.
3) Analog telephone adapters (ATAs) connect your existing telephones to VoIP services. ATAs usually have built-in ADSL modems (Annex A or Annex B, depending on your country) and, in addition to VoIP telephony, are capable of providing the computers in your home with broadband-access to the Internet. In Europe, and probably elsewhere, the ATA currently is the best tool for Voice over IP.
Session Initiation Protocol
Like any other application on the Internet, telephony services need to communicate by an established protocol. VoIP services that use the Session Initiation Protocol (SIP) benefit from the fact that SIP was designed as an open standard. As a result, any SIP-capable device should be able to link up with any other. What this means is that everybody can call anybody else and for free.
Why Not Use Skype?
Skype is an example of a VoIP service. It helped start the VoIP revolution. However, there are two main reasons why using Skype puts you at a disadvantage: 1) Skype is a closed system that uses a proprietary protocol so that 2) they can charge higher rates for additional services.
Service Providers
Connecting a call over the Internet is the basic task of an Internet Telephony Service Provider (ITSP). Additional services, such as voicemail and incoming numbers that can be dialled from normal telephones, are often available at no extra cost.
Skype are by no means the only culprits when it comes to selling their customers short. The fact that a service provider is using SIP to connect your calls does not always equate to a service that is open and free from artificial restrictions. In particular, beware of providers that proclaim to offer a SIP-based service but then disable the facility to call users on other networks for free.
Because dedicated SIP devices can manage up to ten different accounts simultaneously, there is no need to limit yourself to just one provider. Pick and choose to create a mix of services that best suits your telephony requirements.
Expect No Less
So what should you be looking for in a good SIP provider? The first thing to bear in mind is that when it comes to setting things up, SIP is very much like email. On signing up, a provider should issue you with a username, a password, a SIP address and information about their SIP registrar. If any of these are missing or not documented, for whatever reason, just find another provider who does not keep this information from you.
Your SIP provider should offer a gateway to the Public Switched Telephone Network (PSTN), enabling you to make calls from your internet telephone to regular landlines and mobiles. Not all providers charge the same rates, so compare their respective tariffs. Billing should be by the second, and not the nearest minute.
Often there is a telephone number that others can use to call you on your internet phone. Be sure to find out what rates apply to calls to such a number. True geographical numbers are best, as they will always be charged at the same rate as regular numbers with the same area code.
Your SIP address should work exactly as you would expect, in that anyone with a SIP device or compatible software should be able to use the Internet to call you for free. Otherwise, you might as well be using Skype and never really experience the power of true Voice over IP telephony.
www.bluesip.net, www.dus.net, www.voipuser.org
Articles
What Is VoIP
“To the enterprise network engineer, it’s a way to simplify the corporate network and improve the telephony experience. To the home user, it’s a really cool way to save money on the old phone bill.” Theodore Wallingford explains why VoIP is such a big deal.
www.oreillynet.com
Silos Are for Grain, Not VoIP
“The ability to lose is ours according to Microsoft, Skype, Vonage and many others in the mix.” Erik Lagerway argues that VoIP, the biggest show on the Internet, is being undermined by some of the largest players in the industry.
gigaom.com
Crowning the King of Free Talk - Skype vs Gizmo
“While both Skype and Gizmo offer the ability to call anywhere in the world using a computer, they could not be more different when it comes to how this is actually accomplished.” Derek Boiko-Weyrauch takes a balanced look at advantages and disadvantages of the two telephony clients.
www.tomsguide.com
Breaking Down VoIP’s Walls
“The real price of hardware-tying may come in the form of consumer backlash. Imagine Mom’s confusion when she finds that her Microsoft phone can’t make free calls to your Skype phone.” Om Malik looks at VoIP provider’s efforts to lock you in with special hardware.
money.cnn.com
Telecom Terms and Concepts
“Familiarity with terms and concepts will help consumers as they start investigating VoIP services and products. Not all ITSPs are the same, and understanding how your current service is provided will allow you to compare service offerings and avoid surprises”, argues Sean Walberg.
www.oreillynet.com
Unified Home Networks with the FRITZ!Box
“The FRITZ!Box offers you freedom of choice. You can use your own FRITZ!Box with any operator and fine-tune your home network to your needs.” Guylhem Aznar shares his experience.
www.linuxdevcenter.com
Software
Gizmo Project
Gizmo Project is a software client that turns your computer into a VoIP telephone. It is easy to install and employs the Session Initiation Protocol to route your calls. SIPphone, the VoIP service provider behind Gizmo Project, offers free voicemail and call forwarding to other SIP adresses on the Internet.
www.sipphone.com
Help
VoIP Forum
Interact with other VoIP users to help with your questions.
www.voipuser.org
IP Phone Forum
In German
Interact with other VoIP users to help with your questions.
www.ip-phone-forum.de