Since the appearance of video intercom systems in the 1990s, it has played an important role in security system after more than 20 years of development. From the earliest analog non-visual intercom to late video intercom, it realizes communication between visitors and masters. Later it adds a series of functions, such as unlocking, security management, alarm network, which bring many users real experience. With the development of network technology, TCP/IP protocol and digital audio video intercom appear in 2004. Video intercom which be based on network data transmission mode causes great repercussions in industry. And it seems to have the opportunity to replace analog video intercom. With the development of security intelligence, video intercom system is necessary to develop towards network, digital and high-definition in order to meet users’ higher requirements. IP Intercom system has the following five advantages:
Simple Wiring: Compared with the transmission of analog video intercom, IP intercom system is more convenient in wiring and installation. It greatly simplifies wiring project and makes installing and debugging residence intercom system easier, also construction period would be shortened.
Powerful Network Interconnection: When all the signals digitized, it is easy to realize network interconnection. IP intercom system is just like a small computer, strengthening data processing ability makes network interconnection come true and stronger.
Better Expand Ability: IP interconnection has very powerful expanding ability, it not only realizes visual intercom, but also multi media information publishing, radio, security alarm, smart home, video monitoring functions, etc.
Lower Composite Cost: From installation and wiring, IP intercom system use TCP/IP transmission mode, which can save a lot of cost, furthermore, short construction period can save cable and labor cost, it also makes maintenance easier, so using IP intercom system has more advantages in cost.
Longer Transmission Distance: Now development scale of the community is becoming wider, analog video intercom system can use video amplifier to extend a few kilometers of transmission distance, but it cost too much. Compared with fiber optic transmission, currently IP intercom system uses broadband carrier technology to realize long transmission distance in low cost, which has more advantages.
Broadband Carrier Technology: It is a kind of active equipment using twisted pair transmission network data signal, supports both point-to-point and point to multi-point connection and also realizes simultaneously transmit a variety of signals, such as network, power, audio, data, etc via any pair of two-wire.
IP intercom system needs the following signals when transmitting: power supply, communication agreement, audio and video signal. Now main stream intercom system often use 15V, 18V, 24V, 30V DC power supply, communication protocol usually use manufacturer’s independent protocol, such as RS485, CAN-BUS, etc. Video and audio signal use H.264 codec digital signal.
Fiber optic can transmit long-distance and high-fidelity digital audio and video signal, but it has some limitations:
High Cost: Optical module installation is necessary in each splitter and controller of system, whose construction and installation cost is 60% higher than analog transmission video intercom system.
Difficult Wiring: Workers must dig large area of groove because volume of fiber outside is very huge and they are completely buried into the ground, it also requires more workers to operate in the wiring process and the configuration of branch circuit has more troubles.
Transmitting Power Signal is Unavailable: The characteristics of optical cable decide that it couldn’t transmit power signal. In intercom system, low voltage power signal transmission together with cable is very necessary.
Features of Ethernet Media Converter:
◆ Long distance transmission up to 2,000m over RG59.
◆ High speed modulation and demodulation technology, duplex network, maximum physical bandwidth up to 240Mbps.
◆ Transmitting high-speed data network signal over any pair of two-wire.
◆ Support power with cable transmission taking advantages of EoC technology.
◆ Simple device configuration, transparent transmission, dispensing with adjustment and changing on upper software
◆ Low power consumption, active adjustment on communication channel, high performance on error correction coding technology.
Application diagram:
Ethernet Media Converter can be applied in varied network system construction and extension. It has low requirements on cables and installation so that it can be applicable for more environment requirements.
