Another type of field switchboard when packed for transit resembled a salesman's trunk. It was used in the camps and provided for 40 lines. This board was being constantly redesigned as field needs developed. A new type of camp switchboard was coming into heavy production at the end of hostilities.
Still a third type of portable switchboard was built in units resembling the units of a sectional bookcase and was set up in the same way.
The telegraph apparatus of the lines of communication in the S. O. S. was designed along purely commercial lines. It included the latest type of printing telegraph equipment, the apparatus first adopted being the multiplex printing telegraph as used by the Western Union Telegraph Co. Later, the Morkrum printing telegraph was also adopted.
At the close of hostilities 133 complete telegraph stations with full equipment were in operation in the service of supply. The peak load of this service, just prior to the armistice, was 47,555 telegrams, averaging 60 words each, sent from these stations in a single day. The daily average in the final weeks of the fighting was 43,845 telegrams.
RADIO.
At the outbreak of the war, the field radio equipment in active use by the Army was limited to two sets, both of comparatively high power. On the other hand the allied forces had developed a complicated and extensive use of radio sets of small power, many of them operated from airplanes, and the Signal Corps found itself confronted with the task of developing an entire new line of complicated electrical apparatus, and putting it into large quantity production in the shortest possible time. The progress made is indicated by the fact that at the signing of the armistice the number of types of complete sets on which development work had been carried out was 75. Of these approximately 25 were in quantity production. When it is remembered that each of these sets consisted of hundreds of parts, many of which required careful study and experimentation as well as design, the magnitude of the problem is appreciated.
The initial step in the reorganization of this branch of the Signal Corps' work consisted in the establishment of a radio section in Washington and a corresponding section in France. The former was charged with the design of apparatus and the preparation of manufacturing drawings and specifications, while the latter served as the first hand observer of actual service requirements and approved all equipment before it was used in the field. An important auxiliary of the development organization in Washington was the radio laboratories established at Camp Alfred Vail, where all necessary technical facilities, such as model shops, drafting rooms, research laboratories, a completely equipped flying field, etc., were maintained. With this engineering organization and the production organization which handled all Signal Corps equipment, the work here detailed was carried out.
Shortly after the declaration of war, the French government sent to this country a distinguished commission which included the foremost radio experts, who were thoroughly familiar with the latest military developments. Technical information and samples of radio apparatus were also obtained from British sources. With this beginning, the engineering work naturally divided itself into two general problems—first, to duplicate the approved foreign designs, and then to create designs for new types of apparatus which would be superior to any in service. Work on these two groups of problems was prosecuted simultaneously with the result that there were soon in production American equivalents of a number of French and British sets, together with improved original types of American radio apparatus.
