Arm Mbed OS support forum

Switch from data mode to at command mode


I hope that you are fine.

In fact, I’m using mbed STM32 and SIMCOM 7000 4g moule to implement an Iot service with mqtt.

over my STM32 i have just a one UART serial port, that i use it to connect to internet :

network = CellularContext::get_default_instance();

network ->connect();

eventually i want to interrogate the 4g modem in order to get info such us CPIN for example, so i have to switch mbed from Data mode to AT command command over the UART, but, in the reference document :

“PPP mode does not allow AT commands after connecting to data mode”

actually i want to know,we a way that switch mbed from data mode to at command in cellular features ?

thanks in advance.


Typically it is done with cmux or MUX (07.10) multiplexing protocol. It embeds several “virtual” AT’s in a single UART. Simcom implementation is buggy a bit (SW flow control for example) but allows you to read SMS, get SNR and GPS position while holding PPP.