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How do I perform/use modem diagnostics?

Updated over a month ago

For encoder running version 8.7.2 and above it is possible to query the modem and run a list of diagnostic queries, using standard AT commands.

Log into your encoder's local web interface, and select your modem from the Communications page. On the right-hand menu, there should be a Download modem diagnostics menu option:

This will prompt you to run the queries, and then download a TXT file with the results.

There should now be a file called [Model]-ModemDiagnostics.txt in your Downloads folder. If you open this file you will see the textual response to each query:

Manufacturer: Sierra Wireless, Incorporated
Model: EM7421
Revision: SWI9X50C_01.14.22.00 ba8ef1 jenkins 2022/11/11 09:59:48
IMEI: 3562810268204
IMEI SV: 15
FSN: 8G15250501B1
+GCAP: +CGSM


OK

======================================= 

...

It is beyond the scope of this article to document the response to every AT command that is queried. To help please refer to the list of AT commands queried to see which relates to your area of interest.

If you are unfamiliar with AT commands, the best approach to interpreting the output is to paste the contents into an AI Assistant such as ChatGPT, Google Gemini, or Microsoft CoPilot. These tools will summarise the report and allow you to request fuller reports on any area of interest.

Example AI Assistant report


Certainly! Here's a more detailed report based on the diagnostic information provided:

Sierra Wireless EM7421 Modem Diagnostic Report

1. Device Identification

  • Manufacturer: Sierra Wireless, Incorporated

  • Model: EM7421

  • Firmware Revision: SWI9X50C_01.14.22.00

  • IMEI: 356281110268204

  • FSN (Factory Serial Number): 8G150225880501B1

  • PRI Part Number: 998809853

  • PRI Revision: 002.007

  • Customer: Generic-M2M

  • Carrier PRI: 9999999_9907259_SWI9X50C_01.14.22.00_00_GENERIC_002.057_000

2. SIM and Network Status

  • SIM Status: READY

  • Network Operator: STREAM

  • APN (Access Point Name): stream.co.uk

  • IP Address: 10.67.170.127

  • Primary DNS: 17.31.4.129

  • Secondary DNS: 17.31.4.193

3. Modem Operational Status

  • Current Time: 2758 (likely a timestamp)

  • Temperature: 38°C

  • Reset Counter: 9

  • Mode: ONLINE

  • System Mode: LTE

  • PS State: Attached

  • LTE Band: B3

  • LTE Bandwidth: 15 MHz

  • RSRP (Reference Signal Received Power): -90 dBm

  • RSRQ (Reference Signal Received Quality): -8.8 dB

  • SINR (Signal to Interference plus Noise Ratio): 7.8 dB

  • Cell ID: 2651905

  • TAC (Tracking Area Code): 3717

4. Power and Temperature Management

  • Temperature State: Normal

  • Current Temperature: 37.00°C

  • Voltage State: Normal

  • Power Supply Voltage: 3321 mV

5. Firmware and Configuration

  • Preferred Firmware Version: 01.14.22.00

  • Current Firmware Version: 01.14.22.00

  • Preferred Carrier Name: GENERIC

  • Current Carrier Name: GENERIC

  • Preferred Config Name: GENERIC_002.057_000

  • Current Config Name: GENERIC_002.057_000

6. Error and Reset Information

  • Total Reset Count: 188 (indicated by the RESET=HARD,COMMENT=Count entries)

  • Error Logs:

    • gpstask: 04147

    • bsio: 00578

    • rfant: 00412

    • sys_eplm: 00591

7. Additional Settings

  • GPS Enable: 0x01

  • SIM LPM (Low Power Mode): 0x01

  • USB Serial Enable: 0x01

  • Single APN Switch: 0x01

  • QXDM Log Enable: 0x01

8. Commands That Failed

  • AT!VERINFO

  • AT!FLOG?

9. Thermal Management Status

  • Device Levels:

    • pa: 0

    • modem: 0

    • cpuv_restriction_cold: 0

    • modem_current: 0

    • cpr_cold: 0

    • vbatt_low: 0

10. Overall Assessment

  • The modem is currently operational and connected to the network.

  • The temperature and voltage levels are within normal ranges.

  • There have been multiple hard resets, which may indicate stability issues or frequent power cycles.

  • Some commands failed to execute, which might require further investigation or a firmware update.

What AT commands queries are run?

Each of the following AT commands is queried. This list was chosen to provide as full a report as possible and will include commands that may not be supported, return duplicate or irrelevant information.

  1. ATI
    Returns basic information about the modem, including manufacturer, model, revision, IMEI, and GCAP.

  2. AT!PRIID?

    Reports the current PRI (Product Requirements Information) being used, including part number, revision, customer, and carrier PRI.

  3. AT+CPIN?

    Checks the SIM card's PIN status, indicating whether it is ready, requires a PIN, or is locked.

  4. AT+CGDCONT?

    Gets the current list of defined PDP (Packet Data Protocol) contexts, including context ID, PDP type, APN, PDP address, data compression, and header compression.

  5. AT!GSTATUS?

    Provides the current status of the modem, including time, temperature, reset counter, system mode, PS state, LTE band, LTE bandwidth, LTE channels, EMM state, RRC state, IMS registration state, signal quality, and cell information.

  6. AT!PCINFO?

    Shows if the modem is in Low Power state and what might have caused it, including state, LPM voters, and LPM persistence.

  7. AT+COPS?

    Returns the current mode, registered operator, and radio access technology.

  8. AT+CGCONTRDP

    Returns active PDP parameters such as APN, IP address, subnet mask, gateway address, and DNS addresses.

  9. AT!SELRAT?

    Reports the Radio Access Technology (RAT) mode, although it is recommended to use AT!BAND? instead.

  10. AT!BAND?

    Reports the current band configuration, including index, name, and masks for GW, L, TDS, and L bands.

  11. AT!IMPREF?

    Reports the preferred and current firmware and PRI versions.

  12. AT!SECBOOTCFG?

    Used to query the secure boot configuration of the modem.

  13. AT!VERINFO?

    If available, is used to retrieve detailed version information about the firmware and software components of a modem

  14. AT!FLOG?

    Returns a detailed log of events, useful for fault investigation.

  15. AT!IMAGE?

    Reports the firmware versions and PRI files installed, including type, slot, status, LRU, failures, unique ID, and build ID.

  16. AT!HWID?

    Displays the device's hardware version number.

  17. AT!PCTEMP?

    Returns the module's temperature state and actual temperature.

  18. AT!PCVOLT?

    Returns the module's power control supply state and actual voltage.

  19. AT!PCOFFEN?

    Indicates or sets the Power Off Enable feature state, determining the modem's behavior when W_DISABLE is asserted.

  20. AT!ERR

    Displays diagnostic information, including logged error conditions, for technical issue resolution.

  21. AT!GCDUMP

    Displays crash dump data, if available.

  22. AT!CUSTOM?

    Returns several customization values, such as GPS enable, UIM2 enable, SIM LPM, USB serial enable, single APN switch, and QXDM log enable.

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