Phone Calls Over the Internet?

Lasa logo By Lasa Information Systems Team

It has been possible for some time to make voice calls using your existing Internet connection. This article explores why organisations may want to do this, what equipment is needed, the various options, and limitations of the technology.

Why make phone calls over the Internet?

Organisations could be saving money on telephone calls.

Whilst you're connected to the Internet, you're already paying your Internet Service Provider (ISP) a fee for the privilege. It could really make sense for you to avoid paying extra phone charges by making your voice calls over the Internet. Proprietary messaging services and a standards-based technology known as Voice over Internet Protocol (VoIP or Voice over IP) mean that you can make voice calls over the Internet either completely free or for significantly less than the cost of a traditional phone call.

Organisations most likely to benefit from these cost reductions are those that need to make lots of long distance phone calls, particularly abroad. This includes organisations that work internationally, but could also apply to organisations with lots of staff working remotely in other parts of the country or abroad.

Small organisations that already have computers and an Internet connection, and where staff work from home because there is no office, could also benefit, even if they are just making local calls. Many organisations will already have much (if not all) of what they need to make use of the technology depending on which option they choose. Any extra software required is often free or very low cost. However there may be some extra costs for hardware and services which mean Internet phone calls won't be worth it for everyone. See below for more information.

What will you need?

In order to start making voice calls over the Internet you'll need:

  • An Internet connection (preferably broadband, dial up can work OK with local calls but sound quality may be poor over long distances)

  • A computer with sound card (usually required unless using some hardware phones)

You'll also need:

  • A microphone and headphones (speakers produce feedback and echoes) OR

  • An IP Phone which looks like an ordinary phone with a handset, buttons and cradle, but connects to an Ethernet (network) port on your router or hub OR

  • A special adapter called a VoIP adaptor or ATA (AnalogueTelephone Adapter) that allows you to connect an ordinary phone to an Ethernet port on your hub or router.

Finally you will need:

  • Messaging software (e.g. MSN Messenger) or a software phone program (also called a softphone)

  • An account with a VoIP service provider (or voice messaging service) 

What are the options?

There are several options for making voice calls over the Internet so let's look at each of them in turn:

Proprietary Messaging Software

Real time voice chat over the Internet is possible using proprietary messaging services. Popular services include MSN Messenger, Yahoo Messenger, AIM, Microsoft Netmeeting, and Skype. Proprietary messaging systems provide a relatively simple way of getting up and running quickly. The software is generally freely available at no cost, and easy to set up. Access to the basic service is also usually free. However there are some disadvantages:

  • You can generally only chat computer to computer, and withnusers of the same service (MSN Messenger users cannot voice chat with Yahoo Messenger users for example). This usually means downloading and installing software for each voice messaging service you wish to use. However, developments like PhoneGaim (- messaging software that allows you to connect to most of these popular messaging networks through just the one piece of software, and to make calls to traditional telephones) may mean this becomes less of an issue.
  • Proprietary services tend to be Windows basedcurrently - options for Mac, Linux and Unix users are pretty limited if available at all.
  • Voice quality is OK but may not be great, particularly over long distances or when using a dial up connection to the Internet.

You will need to download and install the latest version of the software on each computer that you wish to make calls to or from. In addition each computer will need to have a sound card, microphone and headphones (or IP phone). You will also still need to set up an account with each messaging service you wish to use.

Voice over Internet Protocol (VoIP)

Many VoIP applications use SIP (Session Initiation Protocol - a standards-based protocol that gets round some of the problems associated with proprietary messaging services and offers greater flexibility). For example VoIP is operating system independent - you can use it on a Mac, Windows, Linux etc. Depending on the method used to connect, VoIP calls may not always be completely free. Even where there is a cost however, it is usually significantly less than calls made on a traditional telephone.

You usually connect through a VoIP service provider of which there are many examples including BT Broadband Talk. For more examples see the list of service providers at and personally use and recommend the award-winning

There are several ways VoIP calls can be made:

Computer to Computer:

There is usually no charge for VoIP calls made from one computer to another (peer to peer). Each computer will need to have software telephone (often called a softphone) installed. The software simulates a real phone, pulling together the computer's microphone, sound card, and Internet connection. Many different companies offer free or low cost software and connection services. Examples include Skype and Xten.

Analogue Telephone Adapter (ATA):

An ATA converts a standard analogue telephone signal from a traditional phone to a digital signal that can be sent over the Internet. With an ATA you can connect your standard telephone to your computer via a small adapter that plugs into your phone socket. The phone cable then plugs into the ATA and you're ready to make VoIP calls using your telephone. Your computer will need to be switched on however. There maybe additional software to install but this is usually pretty straightforward. Many traditional phone companies including BT are starting to bundle ATAs with their VoIP services.

IP Phones:

Also known as e-Phones, these look similar to traditional phones but plug directly into your broadband router (a device which sends data around networks including the Internet), rather than a traditional telephone socket. The advantage is that you can use a VoIP phone anywhere you have an available Internet connection and network port. Wireless IP phones are also available and potentially allow users to make VoIP calls from any wireless hotspot. Costs for IP phones start at around £70.

USB Internet Phones

These plug into an available USB port on your computer. Prices start at around £25.

So far the options described allow you to make calls to other people who subscribe to a VoIP service. But what if you want to make calls from your computer to users of traditional phones and no broadband connection? Well technology has an answer for this too …

Calls to ordinary telephones

VoIP services are also capable of interfacing with telephones on the traditional PSTN (Public Switched Telephone Network) so you can make calls to "real" telephones using your broadband connection. For example Skypeout allows you to make VoIP calls to ordinary phone numbers all around the world for a relatively small fee.

Many other VoIP Service providers offer similarly low cost services (see the links to service providers above for more information).

Some services only allow you to connect to PSTN phones but not receive real time voice calls from them to your computer, so check to make sure the service does what you need it to do before signing up.

Are there any limitations?

Although VoIP can mean costs savings and be more convenient for some users, it isn't quite ready to be a complete replacement for traditional PSTN phones. Drawbacks include:

  • Dependent on your Internet connection - since VoIP uses the Internet, the ability to make calls will be affected by the quality, speed and availability of your Internet connection. Local calls may be feasible over a dial up connection but for long distance calls to other countries you'll probably need broadband. Also if your Internet connection is down, you will not be able to make or receive VoiP calls.
  • Power supply needed - if the power goes down, your PSTN phone will normally continue working (unless it's a cordless phone). With VoIP, no power means no telephone.
  • Viruses, Internet worms, and hacking- because VoIP uses the Internet, it is susceptible to attacks from these quarters, although this is very rare. Work on solutions to counter this is ongoing.
  • Underpowered computers- VoIP calls can be affected by other applications running on yourcomputer. So for example if you are chatting away on the phone and open another application that uses up your computer's processing resources, call quality will suffer or your system could crash completely in the middle of an important call. IP Phones are independent of your computer and therefore no affected by this problem.
  • Calls to emergency numbers- problematic if the caller is not able to say what their geographical location is, since there is no real way of associating an IP address with a geographical location. It may not be possible to route calls to the nearest emergency call centre, and with some VoIP services you may not be able to make emergency calls at all.In the UK VoIP telephone numbers can be registered with an address in case of an emergency but only works for static phones.

More information

More information on VoIP, including hardware, software and service providers can be found on the following sites:

Copyright © 2005 Lasa Information Systems Team

Creative Commons Attribution

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 2.0 UK: England & Wales License.

Helpful Advice from those Friendly People at DOT-COMmunICaTions