Limited Duty Officer Designators
The Limited Duty Officer (LDO) Community is comprised of 10 designators.
Officer designator codes are four-digit numbers used to group officers by categories for personnel accounting and administrative purposes and to identify the status of officers. These codes identify, through the first three digits, the categories in which officers are appointed and/or designated and through the fourth digit, the status of the officers within the various categories.
623X. . . .Engineering/Repair-Submarine
626X. . . .Ordnance-Submarine
628X. . . .Electronics-Submarine
629X. . . .Communications-Submarine
633X. . . .Aircraft-Maintenance
641X. . . .Administration
642X. . . .Information Systems
645X. . . .Intelligence
649X. . . .Security
653X. . . .Civil Engineer Corps