Military regulations were written to be used by the signalmen to set up, operate, and service the most common radio equipment.
For equipment purchased only in small numbers, the signal equipment mechanic had the manufacturer's original manuals at their disposition.
An in between stage are the brown coloured technical regulations with the instructions for signal equipment mechanics. These military documents were developed for the most commonly used radio equipment to support the signal mechanics. Often, original manufacturer documents were used;the circuit description and the technical instructions for alignment and repair were translated into German. So the signal mechanics did not need a knowledge of fluent English.