METHOD OF TRANSMITTING DATA OVER A PCM COMMUNICATION SYSTEM

摘要

Either one data channel having a high data rate, or several data channels of the same or mixed lower data rate or rates are transmitted in a channel of a TDM-PCM system having a high data rate. The data transmission is performed in synchronism with the PCM system. This is accomplished by having the data frame of the lower data rates related by a multiple to the PCM frame and by adding bits to the data code words to cause equality between the bits of the data code words and the bits of the PCM code words. Further the data is stored in a buffer store, where the bit addition is accomplished, and is read out continuously in the proper channel time slot of the PCM system. To protect against false data frame synchronization due to data code words simulating the data frame synchronization signal, the added bits of certain of the data code words are employed to form a data frame synchronization code word. It is taught herein that conversion from binary coded bits to binary coded ternary code words provides an advantage in transmission of data in a PCM system.