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Universal (RM551E & RM520N)

Dual SIM Auto-Failover

Automatic hardware SIM switching on link loss, high latency, or monthly data exhaustion.

4 min read · Updated

Dual SIM Auto-Failover

For mission-critical internet deployments, QManager supports dual physical SIM slots and eSIM switching.

Hardware Dual-SIM Support#

Quectel RM520N modems feature dual USIM interfaces (SIM1 and SIM2). Switching between slots is executed in hardware via:

AT
AT+QUIMSLOT=1   # Activate Slot 1
AT+QUIMSLOT=2   # Activate Slot 2

Failover Criteria & Hysteresis#

In Resilience > SIM Failover:

  • Primary SIM Selection: Choose default everyday SIM.
  • Failover Threshold: Trigger failover after X consecutive ping failures.
  • Failback Hysteresis: Prevent flapping! Once failed over to SIM 2, QManager will only revert to SIM 1 after SIM 1 has been validated online and stable for at least 15 continuous minutes.