Video conference is one of the greatest achievements of telecommunication technology. This allows two or more locations to communicate via two-way video and audio transmissions simultaneously. It is called visual collaboration and is a special type of groupware.

The technology behind this is digital compression of audio and video streams in real time. Codec which is coder/decoder performs the compression. Up to 1:500 compression rates can be achieved. The resulting digital form of 1's and 0's is then further subdivided, and then transmitted through some network like ISDN or IP. Audio modems are used in the transmission line that uses POTS or the plain telephony network in video telephony, as it converts the digital pulses to or from analog waves in the audio spectrum range.

The other components which are needed for video conference are:

? Video input - allowing you to take pictures or videos of the person like video camera or web cam
? Video output - where the image can be seen, such as a computer monitor or television
? Audio input - microphones
? Audio output - where the final voice can be reached, usually loudspeakers associated with the display device or telephone
? Data transfer - analog or digital telephone network, LAN or Internet