Views:0 Author:Ada Ru Publish Time: 2021-10-14 Origin: 数码科技测评
With the improvement of network bandwidth and the requirements of relevant national policies, the way of family Internet access from telephone line ADSL dial-up Internet access, transition to network cable to the home PPPoE dial-up Internet access, to the common use of optical cable to the home. Compared with the network cable entry method, the FTTH has one more access device,Which is modem. Optical modems are basically equipped by operators (users own expenses)
When broadband installers come to the door, they bring them to the installation. From purchase to installation and setting, no user intervention is required. Therefore, the average user does not know much about optical modems.
Let’s take a look at what an optical modem is. The optical modem is a common name for an Optical Network Unit, which refers to a transceiver device that converts optical signals into electrical signals. It converts the optical signal in the home optical cable into an electrical signal that can be processed by the electronic circuit through electronic devices. Because the optical modem has only one optical cable entrance, the optical modem is also called a single-port optical transceiver.
It is especially important to note that the optical modem is different from the optical fiber transceiver or the photoelectric converter. The optical modem is used in the wide area network, and the latter is used in the local area network (playing a similar role as a network cable). In addition, the optical fiber transceiver only realizes photoelectric conversion, breaking the limitation of the maximum transmission distance of 150 meters in the LAN cable, and does not involve any protocol conversion issues. In addition to the conversion of photoelectric signals, the optical modem also realizes the conversion of interface protocols.
Fiber optic transceivers can be understood as Ethernet equipment that converts electrical signals .that can only be transmitted over short distances into optical signals that can be transmitted over long distances, and are generally used to extend the transmission distance. There is also a situation where companies build high-speed local area networks, using a thin optical cable to easily break through the bandwidth limit, 100M, 1000M self-adaptive, and replacing network cables with optical cables can greatly reduce costs.
In actual use, fiber optic transceivers are generally used in pairs. Fiber optic transceivers are mostly used in local area networks to break the maximum limit of 150 meters between network cables, and are often used for cascading between switches. In addition, some local edumodemion bureaus organize all schools in the urban area into a local area network and access the Internet through a dedimodemed network line. The distance between schools far exceeds the transmission distance of the network cable. The network from the school to the edumodemion bureau through fiber optic transceivers is easy and stress-free.
Because of its large capacity, long transmission distance, low attenuation and many other advantages, optical fiber is currently basically a broadband access method for households or enterprises and institutions. Computers, mobile phones, and various network devices transmit electrical signals. To communimodeme via optical fibers, optical-to-electrical conversion is necessary, and optical modems are indispensable. After the optical cable enters the home, it must pass the conversion of the optical modem signal and the conversion of the interface protocol.
But do you know? The optical modem is divided into two kinds of GPON and EPON, two kinds of optical modems cannot be used in common. The two optical modems support different protocols. EPON is an IEEE standard and adopts a point-to-multipoint structure. The working protocol is simple, and the networking is cost-effective and efficient. And GPON supports a higher rate than EPON, and can bring more users than EPON, but the technology is complex and the hardware cost is higher than EPON. EPON and GPON are just different standards used in the protocol. GPON supports a larger bandwidth, but the operator’s cost is higher.
Through the above analysis, we finally summarize. The optical modem is a network device that performs photoelectric signal conversion and interface protocol conversion after the optical cable enters the home. According to different protocols used, optical modems are divided into GPON and EPON. The former supports more protocols and higher network rates, while the latter is low in cost. Fiber optic transceivers or photoelectric converters are network devices that realize photoelectric conversion. They are used to break through the limitations of network cable transmission and are mostly used in local area networks.