Voice over IP (VoIP) is a protocol that allows users to transmit voice data over an internet connection, essentially allowing you to make phone calls to someone without going through your telecom provider. There are many types of VoIP solutions, some requiring dedicated hardware such as the Cisco IP Phone (see Figure 1) and others based purely on software.
The greatest draw of VoIP is that it greatly reduces the cost of making phone calls, especially overseas calls.
Figure 1. Cisco IP Phone
In this article, I will walk you through a free VoIP application developed by the inventors of Kazaa--Skype. Skype is a free VoIP application that uses a peer-to-peer networking scheme to route users' calls. To maintain voice quality, Skype employs its own proprietary audio codecs for data compression. It also uses data encryption, 256-bit AES (Advanced Encryption Standard), to ensure the privacy of calls.
Skype is currently supported on the following platforms:
You can obtain Skype from the company's download page. After the installation, you will be prompted to register for your account, which is free (see Figure 2).
Figure 2. Signing up for a Skype account
The Skype application contains three tabs (see Figure 3):
Figure 3. The Skype application--click for full-size image
The first step you take after installing Skype is to test your microphone and speaker setup. Go to the Dial tab and type in
echo123 at the bottom of the application (see Figure 4). Click on the green button to dial the number. This is a test service provided by Skype to let users test their speaker and microphone. You will be greeted by a voice and then asked to record a message of up to 10 seconds, after which the message will be played back. This allows you to verify that your microphone is connected and functioning correctly.
Figure 4. Dialing the echo service
Tip: For best voice quality, use a headset (see Figure 5). Better still, use a Bluetooth headset (see Getting Your Bluetooth Headset to Work in XP to learn how to set one up with Windows XP). Using a stand-alone speaker with a microphone results in echoes and makes the voice call experience quite unbearable.
Figure 5. Use headsets with Skype for the best voice quality
Once you are all set up, you're ready to roll. Now you just need to find people to chat with. It's simple to build a roster of contacts--click on the Add a Contact link in the Contacts tab (see Figure 6) and enter the Skype name of the person (or his or her phone number).
Figure 6. Adding a contact
If you aren't sure what your friend's Skype name is, use the search function (see Figure 7). You can search based on a wide range of criteria.
Figure 7. Searching for a user
In order to add a person to your list of contacts, you need to request authorization (see Figure 8). After you are authorized, you will be able to make calls to him.
Figure 8. Sending an authorization request
If you have been authorized, you will see the person's information (see Figure 9), as well as his picture, if he has included one.
Figure 9. Information appears in the Contacts list
To call a contact in your Contacts list, simply double-click on the contact name, or right-click on the contact and select Call This Contact (see Figure 10).
Figure 10. Calling a contact
When you receive a call from another Skype user, a notification window will appear in the system tray (see Figure 11).
Figure 11. Someone is calling you
Making phone calls between computers using Skype is free. However, if you need to call a regular phone or let others call you using their phone, you need to subscribe to additional services provided by Skype.
While it's free to make calls between computers running Skype, you still have to pay to make calls to a traditional landline (or mobile phone). To make calls to a conventional line, you need to purchase credits (known as SkypeOut) from Skype. Check out the Skype rates. In a nutshell, the rates to make calls using SkypeOut depend on where you are placing the call to, not where you are calling from.
While SkypeOut allows you to make calls to a conventional line, the reverse can also be achieved using SkypeIn. Using SkypeIn, a person using an ordinary phone can call your Skype account on your computer. SkypeIn assigns you a phone number where callers can reach you. For more information on SkypeIn, check out the SkypeIn page.
Skype Voicemail comes free with SkypeIn and lets you send and receive voice mail on your computer. Using Skype Voicemail, you can record voice mail to send, or listen to voice mails that callers left while you were away. Get more information on the Skype Voicemail page.
Besides voice calls, you can use Skype as an instant messenger. Figure 12 depicts two people chatting with each other. You can also invite more users to join the chat by clicking on the yellow "Add more users to this chat" button.
Figure 12. Chatting using Skype
Skype also supports file exchanges (see Figure 13). This is a good utility for the quick transfer of files from one person to another. (It works great if you have multiple computers at home or in the office too! To send files to another person, simply right-click on the contact name and select Send File.
Figure 13. Sending a file to another user
One of the strengths of Skype is its multiple-party voice conferencing. Using Skype, you can have up to a five-way conferencing call. Note that one of the conferencing participants must be the host, and only the host can invite participants to the conferencing. More importantly, the host should be the one with the best internet connection.
To invite someone to a conference, click on the name of the contact and select Invite to Conference (see Figure 14).
Figure 14. Inviting someone to a voice conference
Participants will be able to see who is in the conference (see Figure 15). I have tried a four-way conference, and the sound quality was very impressive.
Figure 15. Viewing the participants of the conference
Besides the various call and conferencing functions, Skype adds a nice touch by allowing you to localize Skype to display the language that you are most comfortable with. To change the language, go to Tools -> Select Language and select the language you prefer (see Figure 16). Twenty-seven languages are supported.
Figure 16. Localizing Skype with your choice of language
Figure 17 shows Skype localized in Chinese and Japanese.
Figure 17. Localizing Skype in Chinese and Japanese
I am pretty excited about Skype. I can think of many uses for it, especially in the workplace. Suppose your office has wireless access everywhere (such as on a university campus). Using Skype on a Pocket PC will let you stay connected with your colleagues, making use of the ubiquitous access that wireless technology provides. My personal Pocket PC phone edition device is now loaded with Skype, and I use it as a WiFi phone whenever I have internet access.
Wei-Meng Lee (Microsoft MVP) http://weimenglee.blogspot.com is a technologist and founder of Developer Learning Solutions http://www.developerlearningsolutions.com, a technology company specializing in hands-on training on the latest Microsoft technologies.
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