Multichannel Share Way Telephone Line Expansion Device

Telephone communication is the most widely employed ways of communication in the world.Telephone communication is becoming more and more important as the national economic reform deepens.Dynamic channel borrowing assignment mode is an effective method in communication channel expansion.Although it has been put into practical use in satellite communication and mobile communication ,no one has attempted to apply it to telephone line expansion.In this paper the author expands the telephone line via dynamic channel borrowing assignment mode,ascertains the expansion scheme,designs the circuit of hardware in telephone line expansion device,draws up software programme,analyses the call lose after using the expansion device theoretically and then experiments to verify it.Eight subscribers can share one or two telephone lines with the help of the telephone line expansion device with each phone a sole number.This makes it possible for subscribers to use any free telephone line.thus increasing the number of subscriber and utilization ration of telephone line.In addition.this project makes it possible for expansion subscribers to communicate directly while not to make use of outer line.which further decreased the system call lose.