The “Equipment not equipped for SM” error in SMS (Short Message Service) usually means that the mobile device or network element you’re trying to send the message through doesn’t support short message (SM) functionality — or that there’s a configuration or routing issue preventing SMS delivery.

Here’s a breakdown of the most common causes and solutions:

Common Causes

  1. Subscriber Not Provisioned for SMS

    • The SIM card or subscriber profile on the HLR/HSS isn’t configured to support SMS.

    • The “SMS service” flag may be disabled on the subscriber’s record.

  2. Unsupported Network or Device

    • The recipient’s equipment (e.g., a data-only SIM, IoT device, or VoLTE-only device) may not support SMS.

    • Some LTE-only or NB-IoT devices cannot receive circuit-switched SMS unless IMS messaging is configured.

  3. Routing or Configuration Issue

    • The SMSC (Short Message Service Center) routing tables may be missing or misconfigured.

    • Incorrect MAP or Diameter routing between network nodes (e.g., MSC, SMSC, HLR) can trigger this error.

  4. Roaming Restrictions

    • The destination network may not allow SMS delivery from your network or lacks an interworking agreement.

  5. Temporary Network Fault

    • Congestion or transient signaling issues can cause a “not equipped” error intermittently.

Troubleshooting Steps

  1. Check Subscriber Provisioning

    • Confirm that the subscriber’s profile in HLR/HSS has the “SMS service” enabled.

    • Verify both MO (Mobile Originated) and MT (Mobile Terminated) SMS permissions.

  2. Inspect SMSC Configuration

    • Ensure the SMSC address is correctly configured in the device and in the network routing tables.

    • Confirm MAP/SS7 or SIP/IMS routes to the SMSC are active.

  3. Verify Network Type

    • For LTE/IMS subscribers, ensure SMS over IMS is provisioned if the network is fully IP-based.

    • For 2G/3G subscribers, ensure CS (Circuit-Switched) domain SMS support.

  4. Test with Another Device/SIM

    • Helps determine if the issue is device-specific or network-side.

  5. Check Roaming Agreements

    • If the user is roaming, confirm that SMS interworking is allowed between the visited and home network.