Abstract: A digital interface between at least two subscriber line interface circuits and a processing unit is described. The interface is configured in the form of a parallel interface. The level of an input/output register and of a control register is allocated, as needed, to the connections of the processing unit. These connections can be operated selectively as inputs or outputs. They can also be operated in two modes, depending upon which type of subscriber line interface circuit (SLIC) is connected. The connections of the last-mentioned units are partially operable as inputs or outputs and partially operable only as inputs but in the input case, selectively for various types of input signals.

Abstract: A digital interface of an integrated subscriber line interface circuit is provided. The interface serves for the connection of a signal processor unit. Individual connections are used as signal inputs in signal entry operation of the interface, and as signal outputs in signal transmission operation. Other connections are used as signal inputs in both operating mode, but receive different signals in each operating mode. One group of connections includes two registers with respective associated decoders to enable switching from one to the other, so that the number of operating instructions that can be represented by means of binary signal value combinations applied to the connections is doubled.

Abstract: The basic dual channel pcm coder/decoder arrangement provides PCM/Analogue Codec facilities for use in speech transmission and comprises (a) a pair of transmit channel amplifiers and a pair of receive channel amplifiers controllable for mutually exclusive operation by channel switches and (b) a comparator together with segment-defining ladder networks and associated current steering switching (and compensated current sources). In the encode (A-D), the unit functions as a successive approximation encoder; the particular transmit amplifier creates a voltage condition across the resistors of the two ladder networks and this condition is balanced by the voltage generated by the current sources. A null is consequently produced at the comparator input to govern the PCM output. In the decode mode, both transmit amplifiers are switched "off" and the requisite receive amplifier is switched "on".