AT Commands to configure the modem to use CAT-M1 (LTE-M)

Overview:

Depending on the device used, a specific network selection procedure needs to be chosen:

- If the device supports only CAT M, automatic operator selection can be on.

- if the device supports Cat M and other Radio Access Technologies (RAT) types (2G, Nb IoT), it is needed to define the network selection procedure by setting the scan sequence via AT Commands or restrict the RAT types it can access to Cat M.

Here is an example for Quectel's BG96 (the AT commands starting with "AT+Q..." are Quectel specific)

With the following AT Commands sequence, we force the BG96 to connect to Cat M. It won't be able to connect to any other RAT Type.

# Only scan for CAT-M Networks
AT+QCFG="nwscanseq",02,1
# LTE only scan
AT+QCFG="nwscanmode",3,1
# Search only CAT-M Networks
AT+QCFG="iotopmode",0,1

 For testing purposes or to speed up the network registration procedure, you can limit the registration to one specific network by entering its MCC/MNC as below:

# Set PDP Context
AT+CGDCONT=1,"IP","em",,

# Manually register to Telefonica O2 Germany on CAT-M
AT+COPS=1,2,"26203",8

Check our fully article about BG96 here.