Joint Electronics Type Designation System (JETDS)
From Night Vision Wiki
The Joint Electronics Type Designation System (JETDS) is a system for naming electronic components used by the U.S. military specified in the MIL-STD-196G spec[1].
The night vision devices used by the U.S. military (e.g. AN/PVS-14, AN/AVS-9) all have names based on the JETDS system.
Devices developed for ground forces use the prefix AN/PVS (Army/Navy Portable Visual Search), while devices developed for aviation use the prefix AN/AVS (Army/Navy Piloted Aircraft Visual Search).
When a JETDS designation is followed by a letter, e.g. AN/PVS-7A, it refers to a specific iteration of a given device, with the initial version of the designated device ending with A, the second one with B, and so forth.
