At commands

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OVERVIEW

Note, LTE in cell modem context stands for Long Term Evolution. An LTE modem is a long term evolution modem.

Good starting point article on AT commands, article by Jason Godfrey of Onomondo dot com:

• https://onomondo.com/blog/test-modem-connectivity-with-at-commands/

A second good starting point article to understand basic AT command types and a little history of AT commands. This Engineering Garage article states that there are four types of AT commands, these types being "test", "read", "set" and "execute" AT commands.

• https://www.engineersgarage.com/at-commands-gsm-at-command-set/

^ AT Command Error Codes

• https://www.smssolutions.net/tutorials/gsm/gsmerrorcodes/

^ Nordic Semi 2021 Notes

0520 AT commands sent by firmware app, and special C language escape sequence for percent character:

• https://devzone.nordicsemi.com/f/nordic-q-a/87162/nrf9160-proprietary-at-commands-ie-at-cmng-1-via-firmware-functions
• https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/mob_termination_ctrl_status/xmodemsleep.html
• https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/mob_termination_ctrl_status/xt3412.html

0425 AT%SMODEMSLEEP command . . .

• https://infocenter.nordicsemi.com/topic/nwp_041/WP/nwp_041/sleep_types/psm_sleep.html

~04xx

• https://community.jaredwolff.com/d/116-at-commands-from-application-space

Acronyms used in Nordic Semi nRF9160 and LTE modem documentation:

• https://infocenter.nordicsemi.com/index.jsp?topic=%2Fref_at_commands%2FREF%2Fat_commands%2Fnw_service%2Fcedrxs_set.html&cp=2_1_6_2_0

Power Saving Mode (PSM) command details:

• https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/nw_service/cpsms.html

^ Nordic Semi Online Power Profiler notes

*  https://devzone.nordicsemi.com/power/w/opp/3/online-power-profiler-for-lte


- SECTION - General settings:
  Chip:  nRF9160 rev2
  Network mode:  LTE-M

- SECTION - PSM
  Enable [y]
  Periodic TAU (sec)            . . . a.k.a. T3412 timer
  Active time (sec)             . . . T3324 timer "Lengh of time modem must stay in RRC idle mode before entering PSM, stay reachable by network in case data needed

- SECTION - RRC idle mode
  Enable [y]
  iDRX interval (sec)           . . . "How often User Equipment listens for incoming data on the network."

- SECTION - Data transfer
  Enable [y]
  Data size (bytes)
  Data transfer interval (sec)

- SECTION - Network paramters
  TX output power (dBm)         . . . dynamically adjusted by network provider.
  RRC inactivity timer (sec)    . . . decided by network provider.
  cDRX interval (sec)           . . . decided by network provider.
  cDRX on duration (ms)         . . . decided by network provider.
  cDRX inactivity timer (ms)    . . . radio must remain in cDRX mode for this period before entering DRX mode, this decided by network provider.
  iDRX PDCCH repetitions (ms)   . . . how long radio must "listen" during iDRX interval, set by network provider cannot be set by User Equipment (UE).

- SECTION - SIM card settings
  Clock stop current (uA)       . . . card specified current consumption when card powered at 1v8.
  Enable shut down in iDRX [y]  . . . review AT%XDATAPRFL command and SIM card specifications to see whether card power shutdown supported by card maker.

- SECTION - GPS
  Enable [n]

^ Quectel BG95 commands

• https://forums.quectel.com/t/obtaining-the-serial-number/7092/6 Quectel BG95 command to query module serial number, command AT+EGMR=0,5.