Computer software and commercial unmodified electronics for which the manufacturer maintains design control are not covered.
For example: The type designation is a unique series of letters and numbers which specifies an item.
For example: * Additional info on Installation indicators: ** Additional info on Type of Equipment indicators: The type designation used to specify Groups (assemblies that are used in conjunction with others to function) is made up of a two letter group indicator (from the table below), followed by a dash, a group number, followed by a slash, and 1-3 letters specifying the equipment it is "part of" or "used with" (see Table 1).
For example: A suffix of "(C)" following the type designation number and any modification letters indicates an item which directly contains NSA-controlled cryptographic material.
For example: Maintenance equipment that is given a type designation is set up as AN/xxM, where the first two letters after the slash (signifying Installation and Type of equipment) are followed by an M. However, if a maintenance or test Unit or Group is considered a "part of" the item in question, it does not receive the M signifier.
For example: A change in the power input voltage, phase, or frequency is denoted by addition of the letter(s) "X", "Y", or "Z".
For example: A pair of parentheses surrounding where the type designation number would be located is used to signify an experimental or developmental model.
However, a group or unit type designation that is already linked to a specific system/subsystem/center/central/set may use ( -FT, -IN) if the system/subsystem/center/central/set uses multiple of the group/unit and they are only distinguishable by length.
JETDS was adopted 16 February 1943 by the Joint Communications Board for all new Army and Navy airborne, radio, and radar equipment.
Over time it was extended to cover the Marine Corps and the Navy's ship, submarine, amphibious, and ground electronic equipment.
When the Air Force was established as a separate department, it continued the use of the system for electronic equipment.
The system has been modified over time, with some types (e.g. carrier pigeon -B-) dropped and others (e.g. computers and cryptographic equipment) added.