There are two types of EPON systems: one is a system that uses 2 wavelengths; the other is a system that uses 3 wavelengths. Epon Wifi Onu,Epon 1Ge Wifi Onu,Epon 4Ge Wifi Onu,Wifi Onu, FTTX solution, HGU ONU Shenzhen GL-COM Technology CO.,LTD. , https://www.szglcom.com
With the continuous growth of power grid construction investment projects, as well as the increasing demand for railway electrification and urban rail transit construction, the industry will usher in a broader market. Statistical data analysis shows that China’s power grid investment has grown rapidly since 2003, with a compound annual growth rate of 25%.
At the same time, the competitiveness of domestic companies has risen rapidly, gradually breaking the situation in which foreign brands such as ABB and Siemens dominate the market. State-owned and private enterprises have competed with foreign brands on the same stage.
In spite of this, it is still unable to solve the problem of inadequate transmission capacity of the grid. The investment in urban rail transit infrastructure construction also shows an upward trend. According to market research, six cities, including Beijing and Shanghai, are planning or planning to expand the existing subway network. In addition, there are 25 cities planning to develop urban rail transit. According to the calculation of the demand for high and low voltage switchgear for the Guangzhou Metro Line 3, 46 to 50 sets of low-voltage switchgear equipment are required on an average per kilometer subway line, requiring 15 C-GIS units. Based on this calculation, before 2015, rail transit will require 75,000 low-voltage switchgears and 22,500 C-GISs. In addition, the construction of large-scale projects such as the West-East Gas Pipeline, the South-to-North Water Transfer Project, and airports will also provide a large market space for the distribution switch control equipment industry.
For a two-wavelength system, its downlink wavelength is 1510 nm to transmit downlink voice, data and digital video services; the uplink wavelength is 1310nm to transmit uplink voice and video on-demand and download data request signals. The two-way transmission rate of this system is 1.25 Gb/s, even if the OBD split ratio is 32, it can transmit 20km.
For the three-wavelength system, in addition to the downlink wavelength of 1510 nm and the uplink wavelength of 1310 nm, a transmission window with a downlink wavelength of 1550 nm (1530 ~ 1565 nm) is added. The new window is used to transmit downlink CATV service or DWDM service. The CATV service can be either an analog video signal or an MPEG-2 digital video signal. When the splitting ratio of this system is 32, it can transmit 18 km.
EPON is located between the business network interface and the user network interface, connected to the business node through SNI, and connected to user equipment through UNI. EPON system is mainly composed of optical line terminal (OLT), optical distribution network (ODN) and optical network unit.
In the EPON system, the OLT is not only a switch or router, but also a multi-service providing platform, which provides optical fiber interfaces for passive optical fiber networks. According to the development trend of Ethernet to metropolitan area network and wide area network, OLT will provide 1 Gb/s and 10 Gb/s Ethernet interfaces. In addition to supporting traditional voice, ordinary telephone lines, and other types of T1/E1 interfaces, the OLT also supports SONET connections at ATM, FR, and OC3/12/48/192 rates. The OLT in the EPON can be configured with multiple optical line cards as required to connect with 16 to 64 ONUs. In EPON, the maximum distance from the OLT to the ONU can reach 20 km. If an optical fiber amplifier (active repeater) is used, the distance can be extended.
Power distribution switch develops momentum Smart grid boosts market demand
China's distribution switch control equipment industry is in an unprecedented boom. In the eight years since 2003, the compound annual growth rate of sales revenue of the industry has reached 30%, and the momentum of development has been rapid. According to the "2012-2016 China High Voltage Switching Industry Investment Strategy and In-Depth Research Consultation Report", China's high voltage switch industry will use smart grid construction as an opportunity during the "12th Five-Year Plan" period, relying on UHV AC and DC transmission projects. Enhance the ability of independent innovation, greatly enhance the level of intelligent switchgear equipment, and promote environmental protection, energy saving, emission reduction equipment;