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I can't send SMS to my device due to absentSubscriber error.
I can't send SMS to my device due to absentSubscriber error.

Make sure your device is registered to the network on GSM.

Jakub Kubinski avatar
Written by Jakub Kubinski
Updated over 2 months ago

Environment

  • Onomondo app:

    • SMS console

    • Network Logs

  • Device: applicable to all

Issue

  • I can't send SMS to my device. SMS console shows error: absentSubscriber.

  • I am finding that SMS is not sent even when the device is online and sending data.

  • The SMS console displays absentSubscriber errors. What does it mean?

Solution

Make sure your device is registered to the network on GSM.

  1. Check GSM registration status with AT+CREG? command.

    1. The modem should respond with: 0,5 - registered to a roaming network.

    2. If any other value is returned, attach to the network following device manufacturer's instructions and try again.

  2. Send a test SMS to the device once you see "Attached GSM connection" in Network Logs.

  3. If the issue persists, contact Onomondo Support.

If you are sure that your device is registered with the network on GSM, but the SMS Console returns absentSubscriber, it is possible that the local MSC (Mobile Switching Center) has no memory available to handle SMS at this moment and/or it is prioritizing local SIMs over roaming SIMs, placing your SMS in a queue until memory becomes available again.

Cause

Typically, the absentSubscriber error indicates that the network cannot locate the device in the system that handles SMS routing, even though the device may be attached to the network for data services.

In general, there are 3 types of SMS transmission protocols.

  • SMS through the circuit-switched domain (GSM MAP)

    • This protocol is supported by Onomondo.

    • The SMS is handled by the local MSC (Mobile Switching Center) and Onomondo's SMSC (SMS Center).

    • This protocol requires the device to register with the network for GSM services.

    • GSM registration is performed through an updateLocation sent from the RAN, to which Onomondo replies with insertSubscriberData. The response has to be accepted by the RAN.

  • SMS over NAS (MME / Diameter)

    • This protocol is not supported by Onomondo due to absence of features within Onomondo's SMSC that would allow it to read Diameter signaling.

    • This protocol requires the device to be registered with the network for LTE services.

    • In SMS over NAS, SMS is sent via the Diameter protocol to the local MME (Mobile Management Entity) and then passed to the SMSC.

  • SMS over IP

    • This protocol is not supported by Onomondo due to absence of IMS (IP Multimedia System) in Onomondo's core network.

If you intend to use SMS to debug / communicate with your devices, you have to make sure that your device is capable of:

  1. Handling SMS.

  2. Attaching to the network on GSM.

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