In this paper, the authors outline a research multiplexing in the telephone system. Multiplexing is a form of data transmission in which one communication channel carries several transmissions at the same time. The telephone lines that carry users’ daily conversations can carry thousands or even more of conversations at a time using multiplexing concept. The exact number of simultaneous transmission depends on the type of communication channel and the data transmission. Thus the method of dividing a single channel into many channels so that a number of independent signals may be transmitted on it is known as multiplexing.