Abstract: For the transmission of information, such as voice and data that it is necessary to keep secret, it is standard to encode the information at the transmitting side in the digital level and to in turn decode the encoded information at the receiving side after they have been transmitted. With respect to an economical exploitation of the transmission links, it is standard to combine several signals, or respectively, a plurality of signals on the basis of multiplexing methods. Such digital signal hierarchies are standardized according to the CCITT and, given higher hierarchy levels lead to bit rates of more than 100 Mbit. A solution to the extremely high expense for crypto equipment comprising integrated modules operating at such bit rates, multiplexing technology is employed which makes use of a plurality of encoders and a plurality of decoders that have low power consumption and that are composed of integrated modules constructed in accordance with CMOS technology.

Abstract: An information transmission system with a first user network in which pulse code modulation is used, with transition points connecting the networks. There are also signal preparation and data format adaptation devices in the terminals and in the transition point there is a source network recognition device by which a source network identification symbol is added to the call number from the other user network.