ServLink-Air (SLA) Inspection

Modified on Tue, 30 May 2023 at 09:25 AM

If you are experiencing issues with connecting to your controller using a ServLink-Air (SLA), please confirm:

  • The modem is powered on (power LED is on), connected to the mobile network (M1 LED is solid), and has a signal strength of -110dBm or better (1 or more signal strength LEDs are solid).
  • An LTE-M antenna with SMA male connector is securely fastened onto the "MOBILE" connector.
  • The adapter PCB is securely fastened to the ServLink.
  • The ribbon cable is securely and properly connected to the adapter PCB and the controller.


Power LED

The power LED is located on the bottom left corner of the front panel, near the power connector:

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ServLink is powered


ServLink is not powered

Connection status LED

The connection status LEDs are located on left side of the back panel:

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2G, NB, and M1 LEDs are blinking at the same time

No or bad SIM card (normal for ServLink-E)

2G, NB, and M1 LEDs light up and down in sequence

Searching mobile network operator

2G, NB, or M1 LED blinking

Connected to 2G/NB/M1, no data session established

2G, NB, or M1 LED solid ON

Connected to 2G/NB/M1 with data session

Signal strength LEDs

The signal strength LEDs are located on the right side of the back panel:

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Number of LEDs on

Signal Strength Value (RSSI)


≤ -111 dBm


-110 dBm to -82 dBm


-81 dBm to -52 dBm


≥ -51 dBm

Ethernet port LEDs

At the time of this publication, the Ethernet (RJ-45) port on the ServLink-Air is not used.

Graphical user interface 
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