When testing LTE IoT devices, a simple AT command interface can tell you a lot about how the modem connects to the network.
Here’s an example from a Quectel BG96 (CAT-M) module on the SoftBank network in Japan.
In this test, we control the modem and monitor the attach sequence using AT commands:
AT+CFUN=1 → Turn on the modem
+CPIN: READY → SIM detected and ready
+CEREG: → LTE registration complete
AT+CESQ → Check signal quality
AT+QPING → Ping test to verify data path.
In this example, attach was successful and data connection was setup correctly, ready for field testing.
A simple script was used to automate this test with a timestamped AT command log, helpful for measuring attach times and stability in different network conditions.
In the next post, we’ll look deeper what happens at the protocol level using QXDM? Stay tuned!
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