The Reserve Limited Duty Officer (LDO) Community is comprised of 8 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.
6235. . . .Submarine Engineering/Repair
6265. . . .Submarine Ordnance
6285. . . .Submarine Electronics
6295. . . .Submarine Communications
6335. . . .Aviation Maintenance
6415. . . .Administration
6495. . . .Security
6535. . . .Civil Engineer Corps