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GC31 Cellular Gateway Dual-SIM Support
GC31 Cellular Gateway Dual-SIM Support

Learn how the Verkada GC31 Cellular Gateway supports dual-SIM functionality

Updated over a week ago

Verkada's GC31 Cellular Gateway supports dual-SIM functionality with the ability to fall back automatically.

How dual SIM functionality works

By default, the GC31 comes with 2 SIM slots:

  • Slot 1 (Primary)

  • Slot 2 (Secondary)

All devices shipped to customers have a Verkada data SIM inserted in Slot 2. The Verkada data plan is available to be purchased as a license to allow streaming Verkada video devices (cameras and intercoms).

  • If you choose to purchase the data license for the GC31, you can use the Verkada data SIM for streaming your cameras.

  • If you opt to not buy the Verkada data license, you cannot stream cameras. You have a 30-day grace period before you need to claim the license.

Note: Non-camera Verkada devices do not need a data license. Third-party devices are capped at 1 Gb per month for data.

SIM failover

The GC31 has a state machine that constantly monitors the SIM activity on the LTE modem, as follows:

Example: Failover workflow

  1. Start—The state machine is triggered when the device boots.

  2. Primary (monitor)—The general purpose input/output (GPIO) pin on the LTE modem detects when a SIM has been inserted into the primary.

    1. The GC31 attempts to connect via the primary SIM and pings a backend server every N seconds.

    2. If N number of pings fail, the state machine triggers the failover to the secondary.

  3. Primary (fail)—Trigger occurs if the primary SIM fails N pings.

  4. Secondary (monitor)—Similar to the primary monitor, the modem detects when a SIM is inserted and attempts to connect via the secondary SIM and pings the same backend server.

    1. If the secondary SIM fails N pings, it triggers a failover to the primary.

    2. If a SIM is inserted into primary is also a trigger for going from secondary to primary. An additional check is made by the secondary monitor to see if a SIM is inserted into the primary slot.

    3. If the primary slot GPIO recognizes a SIM, it triggers a secondary failover.

  5. Secondary (fail)—Trigger occurs if a secondary SIM fails N pings or a SIM is inserted into the primary.

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