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Now, most favors fiber access is mainly the EPON fiber access system. Inheriting from the low cost of Ethernet,
usability and bandwidth of optical network, EPON technology is one of the best technologies in fiber access and is
adopted by the carriers all over the world widely.
According to the scheme analysis to FTTH fan-end equipment, hardware design of ONU is proposed in this paper.
The FTTH far-end equipment software design deference modulation design concept, it divides the software
designment into 5 function modules: the module of low-layer driver, the module of system management, the
module of master/slave communication, and the module of main/Standby switch and the module of command line.
The software flow of the host computer is also analyzed. Finally, test is made for Ethernet service performance of
FTTH far-end equipment, E1 service performance and the optical path protection switching, and so on. The results
of test indicates that all the items are accordance with technical request of far-end ONU equipment and possess
good quality and fully reach the requirement of telecommunication level equipment.
The far-end equipment of FTTH divides into several parts based on the function: the control module, the exchange
module, the UNI interface module, the ONU module, the EPON interface module, the network management
debugging module, the voice processing module, the circuit simulation module, the CATV module.
In the downstream direction, under the protect condition, we design 2 optical modules. The system can set one
group optical module working and another group optical module closure when it is initialized. When the optical
fiber line is cut off, the LOS warning comes out. It will cause MUX to replace another group optical module,
simultaneously will reset module 3701/3711 and will make it again test the distance, and will give the plug board
MPC850 report through the GPIO port. During normal mode, the downstream optical signal is transformed into the
electrical signal by the optical module.
In the upstream direction, the upstream Ethernet data is retransmitted through the exchange chip BCM5380 to the
GMII/MII in module 3701/3711, and then is transmitted to EPON port. The 2MB data are transformed the Ethernet
data packet in the plug board TDM, then it's transmitted to the interface MII of the module 3701/3711.
The software design of FTTH far-end equipment compiles with modulation design concept. According to the
system realization duty, the software is divided into 5 function modules: low-level driver module, system
management module, master/slave communication module, the man/Standby switch module and the command line
module.
The FTTH far-end equipment test, is mainly the Ethernet service performance test, E1 service performance test and
the optical path protection switching test and so on the key specification test.
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