Video Conferencing Systems

The Video conferencing system enables people at two or more locations to interact using dedicated two-way video/audio transmissions, that are quick and simultaneous. The technology is also referred to as visual collaboration, which is integrated groupware and is designed to serve conferences.

It brings people at different regions or sites together for a meeting. The conference could involve a conversation between two people (point-to-point) or several sites (multi-point).

In the latter, the technology is designed to cater to exchange of information with more than one person in large rooms and at different sites. Internet video conferencing can be used to share documents and information displayed on whiteboards or even computer-displayed information.

There were simple analog conferences in use, alongside the invention of the television. The systems way back then, comprised two-television systems that were closed circuit in nature and connected via cable. The use of two radio frequency links, one in each direction, is still in use by TV channels, when reporting from distant locations.

This system was first demonstrated in 1968 and back then, the technique was very expensive. It could not be initially used for mundane applications, such as distant education or business meetings. The attempts at employing normal telephonic networks to transmit slow-scan video were unsuccessful due to the poor picture quality and compression techniques.

VTC systems have now evolved from highly expensive proprietary equipment, to components of a standardized technology, that is easily accessible to the general public at an affordable cost. Today, there are more efficient compression technologies developed that enable desktop and personal computer based video conferencing.

The dual plasma display system has a screen that is primarily used to show the user interface when setting up the call. Another screen displays data and even a secondary 'far site' in a multipoint conference. The core technology involves digital compression of audio and video streams.

The coder/decoder is the basic hardware or software that performs the required compression. The resultant digital stream is subdivided into packets that are then transmitted, via a dedicated network.

This network is digital in nature. The modems promoting audio transmission enable the use of the 'Plain Old Telephone System' in certain low-speed applications to convert the digital pulses into analog waves.

The dedicated systems comprise single-piece equipment, which is usually a console and a camera. The cameras can be controlled at a distance. The console has all electrical interfaces, including the computer, the software or hardware-based codec, and omnidirectional microphones. The equipment includes a TV monitor with loudspeakers and a projector.

There are different types of dedicated devices. The large group ones are non-portable, and employ expensive devices for large rooms and auditoriums. The small group VTC comprise non-portable or portable, less expensive devices, for smaller meeting rooms.

There are individual VTC portable devices that are meant for single users. The latter have fixed cameras and microphones within the console. The desktop systems are add-ons that transform regular PCs into VTC devices. They enable the use of a range of cameras and microphones with the board, for the necessary codec and transmission interfaces.

Multipoint video conferencing is simultaneous interaction between three or more remote points. The multipoint control unit is a bridge that interconnects the calls from several sources that are going to participate. The equipment is pure software, but there are others which are a combination of hardware and software.

The efficiency of the unit is analyzed on the basis of the number of simultaneous calls it can handle, along with their ability to conduct transposing of data rates and protocols. These units can be stand-alone hardware devices or otherwise. The convenience and quality comes with increased network bandwidth.