Design And Implementation Of EPON Box OLT Programmable Logic Device And Its Control Circuit

With the rapid development of communication technology,people's living needs are constantly improving,and the types of communication services are becoming more and more diversified.Although the copper wire laying technology is very mature,with the increasing demand for bandwidth access,it can no longer meet the business needs of the next generation network.Because of its low price,large bandwidth,long transmission distance and no interference,optical fiber has become the medium of choice for next-generation network transmission.As a new generation of passive optical network access technology,EPON has great advantages in anti-interference,ranging technology,bandwidth allocation,maintenance management and so on.This project is from the EPON box OLT item EL5610-08 P of Shenzhen National High-tech Enterprise research project.I have completed the research and design of an EPON box OLT programmable logic device and its control circuit in the project.The main contents are as follows:Firstly,serial port switching function of OLT device.In the market,the box type OLT device generally has only one external serial port,and the CPU serial port must be extracted.The CPU and PON chip of the OLT device are not dynamically switched.In this paper,an EPLD device is used to realize a switching process between the CPU and the PON chip with only one external serial port.Secondly,it is providing a simple and flexible device and method for implementing PSG redundancy protection for all PON port links of an OLT device,reducing design complexity and equipment cost,and it is verified by simulating the occurrence of optical link failure.Thirdly,the box OLT device has dual power supply redundancy.The common practice of implementing the dual-power redundancy of the box OLT in the line is to isolate the two power supplies from the anti-backflow double Schottky rectifier.This will cause a certain voltage drop in the anti-backflow double Schottky rectifier,which reduces the power input voltage efficiency.And for low-cost power supplies,it is impossible to monitor the power in-position information.This paper provides a low-cost method for power location detection and redundancy implementation.Finally,we conducted experimental tests on the function to verify the feasibility of the design,and it extended the program to mass production of OLT equipment.This research has brought great convenience to OLT analysis faults on the market,and it has improved the power supply efficiency and it has reduced the design complexity of OLT products and the production cost of the equipment,and compared with the company's EL5600-08 P product,the mass production cost has dropped by about 10%.