Optical Multiplexer: The Focus of Video Conference System Construction

In the 21st century with the rapid development of information technology, the research and application of computer technology and communication technology and optical transmission of optical transceivers have been hot areas. "Video conferencing" provides us with the best means for two-way transmission of images, sounds, and data from different locations. It can be said that we have made meticulous choices for the transmission of optical transceivers, video terminals, and MCU equipment that ensure the smooth operation of videoconferencing. We have the conditions to hold high-quality video conferences.

First, the positioning must be accurate

Each unit must carefully consider its use before deciding to build a videoconferencing system. According to different value orientation to choose the appropriate transmission quality. In general, the quality of service for videoconferencing can be divided into three levels: High quality: The circuit is based on the DDN, E1 private line, and complies with the H.320 network protocol standard of the International Telecommunications Union (ITU). The channel rate should be 2M. The device is Full hardware Codec (Multimedia Digital Codec), 30fpsFCIF format video, rich circuit interface and intelligent voice and other functions.

It is applicable to large-scale backbone video television systems built by state agencies, government agencies, and telecom operators. Medium quality: The circuit is generally based on a dedicated IP network, in line with (ITU) H.323 network protocol standards, the channel rate should be above 768k, the device is also a full hardware Codec, 20 ~ 30fpsFCIF format video, optical transmission hardware is the global technology leader YK Optical transceiver. Suitable for use in a range of office meetings or distance learning. Low quality: Provides pure software Codec, 10fps FCIF format video, based on IP circuit. Meet the (ITU) H.323 desktop video conferencing requirements, the channel rate is below 384k. Meet the simple and simple usage requirements.

The video conferencing system of the Guangzhou Court covers the city's High Court as the center and covers the city's three intermediate courts, as well as 18 district and county courts and 54 dispatched people's courts. It is mainly used for convening conferences in the city's courts and transmitting high-quality trial images.

The choice of network transmission method should be decided according to different values. The primary consideration for the construction of videoconferencing networks in Guangzhou courts is the problem of clear images and stability of the entire network. Therefore, we chose the H.320 protocol and the high-quality E1 private line transmission scheme.

Second, the circuit is guaranteed
In 2001, a videoconferencing system was constructed. Local telecommunications bureaus installed fiber optic cable circuits in various courts, rented 2M transmission circuits using PDH transmission methods, and telecommunication bureaus used SDH transmission methods to interconnect, eventually connecting all circuits to the main venue. 155M optical transceiver, the network is a star structure. The entire circuit is transmitted by optical cable, which lays the foundation for the reliable, confidential and safe operation of the video conferencing system. The video conference enjoys an exclusive 2M bandwidth. In order to ensure stable transmission, the circuit interface adopts the E1 mode to avoid the G.703-V.35 conversion device. Loss and fault potential, the circuit between the main venue Codec-MCU-Optical-Optical Modem-Codec Codec is very simple.

The network protocol complies with the H.320 protocol standard of the International Telecommunications Union (ITU), which allows the image information to be strictly transmitted separately from other network information. This avoids the possibility of data interference between the H.323 protocol and the stable and reliable transmission of the image signal.

Third, the equipment is the key

"If you want to do something good, you must first sharpen its tools." To build a stable and reliable video conferencing network, not only requires good data transmission channels for protection, but also must have excellent video conferencing equipment. Adopt open PC interface and modular design, support H.320 and H.323 dual-protocol modes, easy operation, easy upgrade, powerful multimedia and data transmission functions; data can be processed without affecting image transmission quality Transmission dual stream function;

In VTEL's unique network management software supported by the LAN, the administrator can monitor the entire network running status at the center console; can detect and diagnose system faults at the remote end, can start the device, configure parameters, and can replace the remote The administrator operates the device to realize the intelligent operation and management of the device. In practice, we use this management function to play a significant role in ensuring the smooth implementation of the entire network conference.

Fourth, stability is a requirement

The image multi-point controller (MCU) in the video conference network is a key device in the network. The main functions are: node selection, conference setup, real-time control, resource allocation, data forwarding, protocol analysis, and the like. Whether the performance of the MCU device is stable and reliable will directly affect the quality of the video conference. We have chosen an imported branded product that has been widely used in our country's H.320 network.