Telegraph central office set TC-3 and switchboard BD-100 - USA Voorschrift, Technical Manual, 11-358 Principles of long distance telephone and telegraph transmission - USA Voorschrift, Technical Manual, 11-475 Regulations for United States military telegraph lines, alaskan cables, and telegraph stations u.s. signal corps / prepared under the direction of brigadier general George P. … Signal : Commercial telephone, telegraph and electric time service, general - USA Voorschrift, Army Regulations, No. 105-30 Signal Corps : Telegraph, cable and radio service - USA Voorschrift, Army Regulations, No. 105-25
