Design Of Multi-synchronous Digital Converting & Distributing System Based On CPCI

Multi synchronous digital converting & distributing system will solve the problem that how to transmit multiple (four) business data to the remote terminates through multiple (four) synchronous digital channels. To achieve this goal, we need solving several issues mentioned later. The first issue is how to convert different kinds of data to Ethernet data. The second is dealing with the merged Ethernet data. The third is using a variety of synchronous and plesiochronous digital channel to transmit Ethernet data.This paper adopted the solutions that using industrial control unit as the processing platform which has the CPCI bus, then designing different kinds of protocol converter on the standard built-in CPCI boards as the protocol converting equipment. Linux is used as the operating system whose source file has opened to public. Then a kernel module was written to monitor the synchronous digital channels, and the data was transmited on the link layer.This paper discussed the designing of one protocol converter based on CPCI, the technique that multi-channel E1 transferring Ethernet based on CPCI. This protocol converter adopts RC6105 which is the dedicated IPoverE1 chip to complete protocol conversion, and use the chip RTL8139 to connect with cpci-bus, connects RC6105 and RTL8139 through the switch chip KS8995MA and necessary isolation transformer. This solution realized an IPoverE1 protocol converter which is based on CPCI.This paper also discussed the realization of the software system.The software system is divided into two layers. One is working in the kernel mode, to detect the communicating state of the four synchronous digital channels, and according to the strategy choosed by administrator distributes the business data. Another is application software which is working in the user mode. The application software provides links for remote access service. Besides, it is able to connect remote administrator and kernel module. So, the application software realizes the remote control of the kernel module. And this paper also discussed the detection of all the channels state and the realization of distributing strategy. Besides, it discussed the communication protocol of the moule and the user application.