The following is an excerpt from an article written on the internet.

I am posting this information because I have learned some good tips from this article.

Maybe it will help you in the future.

To see the complete article, including graphics and links, go to: 

http://www.makeuseof.com/tag/6-check-skype-work/

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1  Heartbeat

First thing’s first: If you can’t connect or use a specific Skype feature, check the Skype heartbeat page. You can access this page by clicking the Help menu in Skype and selecting Heartbeat (Skype Status), or by visiting heartbeat.skype.com in your web browser.

The heartbeat page informs you of Skype’s system status – if there are any problems with Skype’s infrastructure, you’ll see them here. If there is a problem, wait for Skype to fix it and try connecting later.

2  Audio Settings
You can test your microphone and speakers from the Audio Settings panel in Skype’s Options window – open the Options window by clicking Tools and Options.

To test your microphone, speak into it – you should see the green volume bar under Microphone move.

Test your speakers in the same way by clicking the green play button to the right of the speakers device. You should hear the Skype call sound. If you don’t, select a different device from the Speakers drop-down box and try again.

3  Audio Hardware
If playing with the options on the Audio settings panel doesn’t help, examine the hardware itself. Some microphones and headsets have volume sliders or mute switches on their cords – you could have accidentally moved the slider or flipped the switch.

Also check to make sure that the microphone and speakers are plugged into the correct port. USB microphones can be plugged into any standard USB slot, while analog microphones must be connected to the correct sound jack. The microphone jack is usually the pink one, although different audio hardware may sometimes use different colors.

4  Video Settings
Assuming you have a webcam, you can configure it from the Video settings pane in Skype’s options window. If your webcam is connected and you don’t see it in this window, you may need to install drivers for it. Drivers can usually be downloaded from your webcam or computer manufacturer’s website.

5  Test Call
If everything seems to be configured properly, try a test call. One way you can perform a test call is by clicking the “Make a free test call” link at the bottom of the Audio settings window.

The call testing service will ask you to speak into your microphone after a beep. It records your call and, after a few seconds, plays your message back to you. This ensures that everything is working properly – your microphone, speakers, and the network connection. If the call worked properly, you should be good to go – if you can’t hear another person on Skype, it’s probably a problem on their end.

6  Bandwidth Usage
If you – or anyone else on your network – is overloading your network bandwidth with bandwidth-intensive tasks like downloading files over BitTorrent or other peer-to-peer networks, you’ll experience poor call quality. One of the obvious signs of network congestion is robotic-sounding voices.

Close any file-downloading programs – both on your computer and on other computers on the network – and try placing the Skype call again.

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You can also get more troubleshooting tips from the call quality guide integrated into Skype. Click the Help menu and select Call Quality Guide to open it.