EPON system uses a single optical fiber 3-wavelength to transmit the whole business, both on the EPON OLT / downlink wave (1310 / 1490nm) through wavelength division multiplexing, digital video for transmission of data, voice and IP exchange (IP- SDTV), the third wavelength (1550nm) for downlink CATV RF transmission. With this design, PON can cover more than 20km 16 within the optical node. HFC network broadcast television signals to achieve, IP, voice, video-on-demand two-way business operates by EPON. EPON downlink: signal transmission of multiple services over the backbone network to the central office (the front end), is then converted to an optical signal OLT, uses the service for the user are broadcast, to the ONU through the PON allocation unit. By ONU optical / electrical conversion and the corresponding post-processing, the address information of each ONU each packet, receiving their own packets. Carried by each ONU Ethernet frame according to the MAC address of the relevant information, determine whether the Ethernet frame is received or abandoned. EPON upstream direction: upstream using time division multiple access (TDMA), and the system performing the ranging delay compensation, OLT different time slots allocated to each ONU according to certain principles of the upward signal light re-entering each ONU common fiber dispenser, just occupy allocated to it a specified time slot, in order to avoid different ONU uploaded data collide with each other interference. EOC, ONU to BAN, the client last 100m ~ 1km still use coaxial cable households, as much as possible to narrow the scope of network transformation, the client configuration EOC ONU module for data exchange. EOC program using existing coaxial cable network resources to solve the last mile access problem, avoiding the huge two-way home renovation project, without affecting the original downlink broadcast television signals, and to provide data transmission capabilities down the line . EPON + EOC coaxial last mile broadband access is more suitable for two-way radio and television network transformation.
1. Low cost, easy maintenance, easy to expand, easy to upgrade. EPON architecture in transit does not require power, save electricity, easy to lay, do not take the community room, without any active optical module, which is a long-term operating costs and management of large cost savings. The most important thing is EPON + EOC access network technology, EPON technology complies light into the copper, fiber to the home trends, and EOC EPON technology solves the last 100m ~ 1km home issues, and leverage broadcasting original equipment investment.
2. EPON systems such multipoint passive optical networks and existing HFC network broadcasting optical network is completely analogous. In the fiber-to-the corridor layout can share the same corridor more than one core backbone fiber and fiber cloth can be flexible according to the actual geographical spectral distribution and the number of users, and access to a large number of users, save a lot of trunk fiber.
3.EPON system is future-oriented technology, entirely based on the Ethernet standard protocols 802.3ah, a high degree of modularity, easy expansion, high return on investment, is the transition to all-IP networks a good choice.
The top and bottom rows of data in the same one-core optical fiber transmission, completely solve the problem of two-way transmission, providing high symmetrical bandwidth. EPON down the line now offers symmetrical 1.25Gbit / s bandwidth.
5. flexible bandwidth allocation and service is guaranteed. Guaranteed bandwidth allocation and have a complete system. EPON can DBA (dynamic bandwidth algorithm), DiffServ, PQ / WFQ, WRED, etc. to achieve the bandwidth allocation for each user, and to ensure that each user's QoS.
The main index of the test method
After ONU and the central office’s installation, choose a little far away from the light contact users with no way to test the amplifier. Test procedure is as follows:
1) Turn on the TV to watch the TV screen has no effect.
2) Use the TV Signal Level Meter to test whether the television signal attenuation, how much attenuation is within the effective attenuation values(how much television signal attenuation, it should regulate how much light receiver).
3) Home coaxial cable connected to the terminal to see the light is shining terminal CAB, CAB indicator lights when the terminal and the central office has been turned on.
4) Test your computer through the network cable connected to the terminal, if the terminal LAN indicator light flashes, then the terminal and the computer is turned on.
5) With the test computer PING gateway detection delay is less than 10ms (Note: does not include the central office just installed after download).
6) Using network management software test whether the requirements of the line attenuation SNR (signal to noise ratio 60dB attenuation of less than ≥50dB).
7) If conditional, the use of special test equipment for signal attenuation, bandwidth, and throughput testing. If you meet all the above requirements, then the access part of the construction has been completed, the Internet, television and data services can be opened at any time.