World Business

Video conferencing is a technology that provides bidirectional communication system for audio, video and data that allows the receptor sites and radio stations simultaneously maintain an interactive communication in real time. This requires using specialized equipment that allows you to make a connection to anywhere in the world without the need to move to a venue.Some programs even allow you to do video conferencing while travelling on private charter jets.

Videoconferencing involves the preparation of the digital signal, digital transmission and processing of the signal being received. When the signal is digitized it is transmitted via satellite or terrestrial at high speeds.

For that videoconferencing should be made to compress the image using a CODEC. The data is compressed on the source computer, compressed travel through a circuit of communication, whether terrestrial or satellite and decompressed at the destination.

2 .- APPLICATIONS

Today video conferencing is a very important part of communications is for this reason that every day will find new applications of this technology among the most common applications in education are:

* Distance Education
* Research and linkage
* Meetings of academy
* Continuing Education
* Executive session
* Symposium
* Conferences
* Conferences
* Courses
* Seminars
* Other

3 .- Who Benefits
Videoconferencing has become a technology that has been affixed to everyone within the FIR, we have focused mainly to provide our services to:

• Students

* Because they can receive an education of high level training opportunities available only at premier institutes.
* Be available to advanced techniques in educational fields.
* Receive knowledge imparted by eminences on every issue.
* Be able to perform any questions to the speakers, in order to get the best answers to your questions.
* Attend conferences without leaving the educational campus.

• Academics

o Allows chair to give away
Maintain communication or face to face with the students without the need to travel to a classroom
or attend conferences without having to leave the campus institutional

• Researchers

or attend important events without the need to travel to the headquarters site
or communicate with colleagues face to face to exchange views
or lectured around the world from a seat

• Officers

or attend events without the need to travel
or able to communicate with staff without the need to be present
Maintain communication or face to face with other staff

• External users
or attend events taking place elsewhere in the world

What are the main consumers of this technology

4 .- TYPES OF LINKS AND TECHNICAL ASPECTS

Videoconferencing systems operate on the same principles. The essential features that count, is the digital transmission and reception.

These links can be established on satellite, cable, fiber optics etc., And their connection speeds can range from 64 Kbps to 2 Mbps in accordance with the bandwidth you have.

At the beginning of the last decade was needed 6 Mbps to transmit videoconferencing, request that the late 80s went to 2 Mbps

Since early this decade, it is possible to transmit Videoconference on lines of 64 Kbps switched digital

The data is compressed on the source computer, compressed travel through the communication circuit and decompressed at the destination.

The quality of the images we see depends on the level of compression and data transmission capacity.
Standards

The market was restricted for many years because videoconferencing units manufactured by different vendors were not compatible.

It is clear that the explosion that we now experience is directly related to the standard developed by the group 3 of the Consultative Committee for International Telephony and Telegraphy (CCITT), which enables video conferencing units from different manufacturers are compatible.

The videoconferencing market point to point was restricted by the lack of support until the rise of CCITT recommendation H.261 in 1990, bringing the videoconferencing market has grown enormously.

Three other factors have influenced this growth, the first is the discovery of video compression technology, from which the standard is based.

By combining the techniques of predictive coding, discrete cosine transform (DCT), motion compensation and variable length encoding, the standard makes it possible to transmit TV images of acceptable quality with low bandwidth requirements, bandwidths have been reduced enough to achieve low-cost communications over switched digital networks.

The second factor that influenced the development of technology VLSI (Very Large System Integration), which reduced the cost of video codec’s. Now chips are marketed by which they can deploy technologies DCT and motion compensation, parts of the standard.

The third factor is the development of ISDN (Integrated Services Data Network, Integrated Services Digital Network), which promises to provide switched digital communications service at low cost.

ISDN basic access consists of two full-duplex channels of 64 Kbps B channels and one called also full duplex channel of 16 Kbps called D.

The H.261 standard is based on the basic structure of 64 Kbps ISDN. This gives name to the title of the recommendation H.261 “Video codec for audiovisual services PX64 Kbps.

Although it will take several years for ISDN is available globally, video codec’s that comply with the H.261 standard can now operate over communications networks currently available.

Standards that the FIR concerned for the transmission of videoconferencing are:
H.320 Standard
The H.320 standards for videoconferencing described point to point and multipoint in the Integrated Services Digital Network ISDN. This standard governs the basic concepts for the exchange of audio and video in the communication process.

H.323 Standard

The H.323 standard provides a basis for communications based on Internet Protocol IP, defining the way the points in the network transmit and receive calls, sharing the capabilities of transmitting audio, video and data.

Digital networks that support video conferencing are:

• ISDN: Integrated Services Digital Network (1 basic access = 2 x 64 Kbps = 1 BRI).

• IBERCOM: high speed digital line (64 Kbps per line).

• Satellite: Hispasat Retevisión-other (nx 64 Kbps per channel)

• Point to Point: Digital lines of 64 Kbps or 2 Mbps

• Multipoint: Digital lines of 64 Kbps or 2 Mbps

The Service we offer is based on different types of connection due to the equipment

Type of links

Point to Point – Desktop

Point to Point – One to Group

Point to Point – Group to Group

Multipoint – Two or most sites linked
Point to Point

Technical Definition: Direct connection between two sites, its management is carried out through bilateral negotiations between the two sites, marking an IP or ISDN number.

Class definition: It is one that can take place the following types of session:

A teacher to a student

A teacher with a group of students

A group to another group

Multipoint:

Technical Definition: Connecting via videoconference between three or more sites, each terminal receives and permanently images of the other rooms and displayed simultaneously on separate screens or one screen using the technique of split screen. MCU is used to make the connection between participating venues.

Class definition: It occurs when communication is established between three or more different sites by a virtual meeting between:

A professor at several students

A group to other groups

Protocols

A protocol is a set of rules for communication between devices (eg computers, phones, routers, switches, etc). The protocols governing the format, timing, sequencing and error control. Without these rules, the devices could not detect the arrival of bits.

Audio Protocols

G.711
G.722
G.728
G.729

Video Protocols

H.261
H.263
H.263 +
H.263 + +
H.264

Parameters

Number of frames per second (fps)

7.5
15
30
60

Window size (resolution)

QCIF
CIF
4CIF

5 .- REQUIREMENTS

Codec

Encoder-Decodoficador, that captures video and audio signals and compressed for transmission to a remote site.

Audio System

Audio System distributes voice signal and receives. As the audio system, can accomplish the following: Acoustic, echo cancellation and noise suppression, adapting to the noise characteristics of the room.

The audio system is formed by:

• Microphones

Wireless and / or Wired

• Speakers

Ceiling or base

• Mixers

• Equalization of the room

• Amplifier

Video System

The video system allows to observe the image of the remote site and local site, can see the slides, graphics, videos, etc.., Locally or to send the remote site.

The video system is formed by:

• Camera Robotics

• Projector

• Television (s)

• Display

• Document camera

Cold lighting and / or warm

• Fluorescent

• dichroic

Links

• Internet

• I2

• ISDN

• Dedicated

Transmission Speed

• 128 kbps

• 256 kbps

• 384 kbps

• 512 kbps or more

The standard transmission speed is 384 kbps

6 .- OTHER HIGHLIGHTS

Other aspects relevant to the adequacy of a videoconferencing room.

• Architectural Fitting

• Acoustic Conditioning

• Furniture

• Adequate lighting

• Automation