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MMSI Not Set

Uniden Marine VHF Radio

Severity: Minor

Source: OnlyErrorCodes.com — Every error code. One place.

Uniden Marine VHF MMSI Not Set — Programming Fix

What Does This Error Mean?

'MMSI Not Set' on Uniden marine VHF means your radio doesn't have a Maritime Mobile Service Identity (MMSI) programmed.
Without MMSI, DSC distress calls and digital features won't work.
Register an MMSI through your country's authority (BoatUS or FCC in US, Ofcom UK), then program the 9-digit number into the radio via menu.
Most Uniden radios allow MMSI to be set only once — get it right.

Affected Models

  • Uniden UM385
  • Uniden UM625C
  • Uniden MHS75
  • Uniden MHS335BT
  • Uniden Atlantis 270

Common Causes

  • MMSI never registered or programmed
  • Radio factory-reset cleared the MMSI
  • Replacement radio not yet programmed
  • Wrong MMSI was entered (radio now locked)

How to Fix It

  1. Register an MMSI.

    BoatUS (US, free for recreational): boatus.com/MMSI.
    FCC (US, required for commercial or international): fcc.gov.
    Ofcom (UK): ofcom.org.uk.
    Industry Canada (Canada): canada.ca.
    Have boat info ready: vessel name, type, length, callsign.
    Most registrations complete online in 10 minutes.

  2. Receive your 9-digit MMSI.

    After registration, you receive a 9-digit number.
    Write it down clearly.
    Save the registration confirmation for your records.
    Don't share — MMSI is tied to your specific vessel.

  3. Open Uniden MMSI programming.

    On Uniden marine VHFs: Menu → DSC Setup → MMSI / User MMSI.
    Exact path varies by model.
    The radio prompts for the 9-digit MMSI.

  4. Enter the MMSI carefully.

    Use the keypad to enter all 9 digits.
    Verify on screen before confirming.
    Most Uniden marine VHFs allow MMSI to be programmed only once.
    Wrong entry locks the radio.
    Have a friend double-check digits before confirming.

  5. Verify and test.

    After confirming, the radio shows the MMSI on home screen.
    Test DSC functions by calling a friend's MMSI.
    Don't test the distress button — that's a real distress signal.
    Use a regular DSC call as a test.

Frequently Asked Questions

Do I really need an MMSI?

If you want DSC distress capability (and you should), yes.
Voice-only VHF works without MMSI but you lose the digital safety features.
DSC distress button sends your MMSI and GPS position automatically — much better than voice mayday.
Free for recreational use (BoatUS).
Register one even if you rarely use the boat.

What if I program the wrong MMSI?

Most Uniden VHFs lock after first MMSI entry.
Wrong entry means sending the radio to Uniden for reset.
Some service centers can help.
Don't rush — verify the digits carefully before confirming.
Have someone else read them aloud while you type.