The subject of the paper is the monolithic integration of digital circuits on GaAs, a technique which is of significance for the subnanosecond range. Planar Gunn devices operated in the triggered-domain mode are used, and the technological requirements of such circuits are described. The limits of GaAs integrated circuits with regard to package density and bit rate are given. A dynamic shift register with Gunn devices for multiplexing and demultiplexing techniques in connection with p.c.m. transmission in the gigabit-per-second range is demonstrated. The technological level attainable at present is illustrated by a dynamic shift register consisting of five monolithically integrated Gunn devices. Experimental results with continuously operating circuits for a bit rate close to 2 Gbit/s are reported.