The PCM-4 PCM Channel Measuring Set can handle practically all PCM multiplexer measurements, and also measurements on the constituent subassemblies of digital exchanges. Transmultiplexer measurements are also possible because investigations between digital interfaces can be made. Single modules may also be checked as it is possible to carry out all measurements via 64 kbit/s interfaces. Compact instrument for A-A, A-D, D-A and D-D measurements to CCITT Rec. O.133, G.700-Series and North American standards (BN984/02). 24-channel version (BN984/02) with "normal/extended" (CRC-6) frame structure to CCITT Rec. G.704 and North American standards (optional). Linking of setups to form and automatic sequence of measurements. Acts as a system controller for MU-30 test point scanner, suitable ASCII printer or graphics plotter (hp-GL) connected via IEC 625 / IEEE 488 bus. A-law and µ-law. Digital signal processing for high accuracy and high measuring speed.