g. Telecommunications centers.
These instructions govern the locations and markings of
telecommunications centers, establish procedures for the transmittal and receipt of documents, prescribe the
records to be maintained, and give other information pertaining to telecommunications center operations.
h. Messenger service. These instructions should indicate the extent of the command messenger service,
including scheduled motor, air, and special messengers. They should indicate pickup and delivery points,
prescribe methods of packaging and addressing, state security clearances required by messengers, and prescribe
methods of marking messenger vehicles.
i. Wire communications. These instructions include assigning responsibility for normal wire lines and wire
and cable construction practices, priority of installations, tagging procedures, and general guidance for locations
for switchboards, patching, and circuit/system control facilities, teletypewriter equipment, and other major
terminal equipment. These instructions may include directory service, circuit/system control procedures,
instructions for obtaining service, and care and maintenance of wire communications material. In supporting
artillery operations, the signal officer ensures that enough serviceable wire is on-hand and that field wiring
diagrams get o those who need them. When possible, wire is recovered for future use before a unit maneuvers to
its next fire mission. Refer to FM 24-20, Field Wire and Cable Techniques, for specific details.
j. Single-channel radio communications. These instructions pertain to the installation, operation, and
maintenance of single-channel radio communications equipment, and the composition and use of radio nets, to
include those required for special purposes and emergency operations. These instructions also define actions to
be taken in the event of jamming and establish procedures for monitoring various frequencies on nets. Refer to
FM 24-18, Tactical Single-Channel Radio Communications Techniques, for specific details.
k. Multi-channel communications. These instructions pertain to the installation, operation, and maintenance
of those multi-channel systems. Detailed instructions on operations should be published in the SOP for the signal
unit that provides the multi-channel system. The signal annex should indicate those facilities that are to be
provided for each major element of the command and prescribe the criteria for their displacement. Refer to FM
24-21, Tactical Multi-channel Radio Communications Techniques, for specific details.
l. Visual and sound communications. These instructions pertain to the general use and distribution of visual
and sound signal devices (arm-and-and signals, flags, lights, panels, pyrotechnic, whistles, sirens, bells, voice
amplifies, explosive devices, etc.). Specific instructions on visual and sound communications are in the SOI and
OPORD. These instructions cover the maintenance of equipment where applicable. Refer to FM 21-60, Visual
Signals, and FM 3-23.30, Grenade and Pyrotechnic Signals, for specific details.