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QManager
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Universal (RM551E & RM520N)

Forbidden PLMN (FPLMN) Clearing

Inspect and clear the Forbidden PLMN list on your SIM card to restore connection to roaming carriers.

3 min read · Updated

Forbidden PLMN (FPLMN) Clearing

When a cellular modem attempts to register on a tower that temporarily rejects it, the SIM card writes that carrier's Public Land Mobile Network (PLMN) ID into its internal Forbidden PLMN (FPLMN) file.

QManager RM551E Blocked networks (FPLMN) screen
RM551E: See whether your SIM is blocking networks and clear the list in one click.

What is an FPLMN?#

Once written to the SIM's FPLMN list, the modem will never attempt to connect to that network again, even if the network issue is resolved and the tower is broadcasting at full signal!

Clearing the FPLMN List#

QManager allows you to inspect and clear the SIM card's forbidden list with one click:

  1. Go to SIM & Profiles > FPLMN Management.
  2. View current forbidden carrier entries (e.g. 310410, 311480).
  3. Click Clear All FPLMN Entries.

Under the hood, QManager writes blank entries directly to the SIM elementary file:

AT
AT+CRSM=214,28539,0,0,12,"FFFFFFFFFFFFFFFFFFFFFFFF"

Screens in QManager#

QManager RM520N Blocked networks (FPLMN) screen
RM520N: Blocked Networks shows the SIM's forbidden network list and lets you clear it.