Digital multiplexing system of the TCC 120 type

Multichannel telephone systems were introduced into Poland's communications network using time division channels. The implications of this problem area have increased significantly in connection with startup of production and the introduction into use of electronic telephone centrals of the E-10 system, which has created, additionally, the need for digital telecommunications transmission systems. For the purposes of meeting these needs, 30 channel telephone equipment of the TCK 30 type was developed and introduced into production and use, using pulse code modulation. The next step in the development of digital systems involves second order digital multiplexing equipment of the TCC 120 type. This equipment serves for multiplexing for time simultaneous digital signals of 2048 kbits/s in the transmission section during a sequence of secondary signals of 8448 kbit/s, as well as the formation of four component signals with the above named speeds in the reception portion.