<![CDATA[DLMS Modem Configuration (Class 45 - Auto Connect & Auto Answer) over 4G/NB-IoT]]>Setting up Cellular Modems via COSEM Class 45 & Class 47

Internal 4G/NB-IoT smart meter modems use Class 45 (Auto Connect) and Class 47 (GSM Diagnostic) for autonomous network registration.

Key Configuration Objects

  • 0.0.2.1.0.255 (Auto Connect): Controls connection trigger (e.g. Periodic, On-Alarm, On-PowerUp).
  • 0.0.25.4.0.255 (GPRS Modem Setup): Holds APN string (e.g. "iot.smartgrid.net"), PIN code, and authentication credentials.
  • 0.0.25.6.0.255 (GSM Diagnostic): Exposes real-time signal strength (RSSI, RSRP, RSRQ), Cell ID, and operator code.

Reading 0.0.25.6.0.255 during site installation allows field engineers to instantly check 4G signal quality directly via optical probe!

]]>https://dlms.sharur.org/topic/42/dlms-modem-configuration-class-45-auto-connect-auto-answer-over-4g-nb-iotRSS for NodeFri, 16 Oct 2026 19:50:43 GMTSat, 22 Aug 2026 12:37:46 GMT60<![CDATA[Reply to DLMS Modem Configuration (Class 45 - Auto Connect & Auto Answer) over 4G/NB-IoT on Sat, 22 Aug 2026 12:37:58 GMT]]>In the modem driver, we configure automatic APN fallback if the primary APN fails DNS resolution after 3 connection attempts.

]]>https://dlms.sharur.org/post/103https://dlms.sharur.org/post/103Sat, 22 Aug 2026 12:37:58 GMT<![CDATA[Reply to DLMS Modem Configuration (Class 45 - Auto Connect & Auto Answer) over 4G/NB-IoT on Sat, 22 Aug 2026 12:37:57 GMT]]>GSM Diagnostic RSSI mapping: Values 0-31 map to $-113\text{ dBm}$ to $-51\text{ dBm}$ ($2\text{ dBm}$ per step). Value 99 indicates unknown or undetectable signal.

]]>https://dlms.sharur.org/post/102https://dlms.sharur.org/post/102Sat, 22 Aug 2026 12:37:57 GMT