Digtial Switching Equipment AXME And Synchronization Clock System

21 century is an information age. Information with low cost, efficiency and the stability is becoming more and more important in the economy. Stored- program control switching, which is one of the cores of the network,serves as the foundation in the Communications Network.Looking back on the developing process of telephone switching of our country, we can devide it into following stages:manual switching★ step by step system switching★ crossbar system switching★ space division switching★ time division switchingThe defination of the exchanging is to deliver the information to the destination where it should go ,according to the fixed rules. Step by step system switching and crossbar system switching realizing the commutation from mannul to automation .Make use of node to complete the conjunction between information source and information destination.Space division switching develops together with microelectronic technique with electronics node replaced by machine node . So the life and dependency are widely incrised. Time division switching which adopts the computer saving technique ,digitalizing the analog ,uses the double port RAM to realize virtual phisical link and greatly improve the reliability , anti-interference and integrativity.This technique highly improves the way of communication .Along with the telephone office digital exchaning equipment technique going mature and business providing ability improving , the equipment has taken the dominant position in the communication network. When the construction of network growing and market economy developing ,network requires bigger capacity ,fewer offices,more business and wider covering.where the equipment running envirment is bad and maintenance technique is low, there is no man to look after the equipment.The problem that manufacture companies have to face is how to make the total amount of breaks below two hours in the 10 years equipment quality time,according to the <>.So that the digital stored-program control telephone switching assistant system comes into existence.In addition to the foreign technique and equipment manufacturing technique , the good condition of running the equipment makes the instrument meet this request. On the other hand the demestic switching machine lacking of the experience and good condition is not qulified for the request ,further more the sofeware of the demestic switching machine can not understand the foundation of the machine clearly .So that the system software inevitably has some weaknesses .The result of this is that the dependency of our machine is not as good as foreign country's .Now demestic switching machine with super network interface widely uses the assistant saving part data and user data when turning off the machine and the time of loading is less than a second . But the CPU are different. For example, some now use the motrola's mc68000, MC360 etc.ARM series with RISC structure and bus structure of Harvard now has taken more than 85% of the market of wireless communication equipment.It is more widely used than other 32 bit CPU and it has high speed ,powerful process ability and multi-interfaces so that we can choose it. Because of the problem of time ,our AXME still has some weaknesses 1 The interface bewteen machine and man is not perfect. 2 The system doesn't has MMU so that the software is not efficient. 3 For the sake of other equipments communication agreement ,this system can only be used in HJD04 series switching machine. Synchronization Clock System is the sub-system of AXME. See the following picture : The system is the key to realize Synchronization network with the head-office equipments .All the distribution of the data are controled by the synchronous signal provided by the system .It is compatible with HJD04 and D machine .And it provides...