Marine Corps · MOS history

0621 Field Radio Operator (PMOS)

MOS 0621 changed from Field Radio Operator to Transmissions System Operator, retaining the same code and primary MOS (PMOS) status. The table also marks a revised description and changed requirements, rather than a title-only rename.

The directory also lists 0621 Transmissions System Operator. Current service use is not established for this directory entry.

Codes named in this history

Listed in today's directory

These codes have directory pages; their current use has not been reviewed, so no current claim is made here.

Documented history

Field Radio Operator (PMOS)

1 October 2017 is the scheduled active-component batch conversion date in paragraph 4001.1b. Paragraph 4002.2 instead prints 1 October 2008, a conflicting date; the 2017 date follows the FY18 implementation schedule.

  • The cited material identifies description and requirement changes but does not explain their details.
  • Reserve retraining for Prior Service MOS Retraining Program, Active Reserve and Selected Marine Corps Reserve Marines was required as applicable and subject to available funds; entries for Individual Mobilization Augmentees, Individual Ready Reservists and Standby Reservists were separately authorized by the headquarters conversion action shown on the unit's Diary Feedback Report.
  • Formal schools and training detachments were to continue awarding current MOSs until a MARADMIN directed implementation.
Source extraction notes

Source new title: Transmissions System Operator (PMOS). Figure 4-1 remarks: 2, 7. NAVMC 1200.1C (FY18) paragraph 4001.1b schedules the active-duty-component MCTFS batch for 2017-10-01. Paragraph 4001.6 separately addresses Reserve retraining, subject to available funds for the specified groups, and records for Individual Mobilization Augmentees, Individual Ready Reservists and Standby Reservists. Paragraph 4002.3 keeps formal-school MOS awards unchanged until MARADMIN implementation direction. The scheduled batch date is not proof of an individual's qualification, retraining or record-update completion. Paragraph 4002.2 prints 1 October 2008, in conflict with the 1 October 2017 schedule in paragraph 4001.1b. The recorded date follows the edition-specific schedule in paragraph 4001.1b; the conflicting printed instruction is not silently corrected.

Source documents (1)

Reviewed September 24, 2026 against references 1, 2 and 3.

Historical information is drawn from the sources linked above. Classification dates are not personal service dates. Spot an error? Let us know.