FX30S Serial port stopped communicating

Hi all,

I’ve come across a problem with my FX30S where initially it is working great for about 3 or 4 days, then suddenly stops working. If I reboot/cycle power, it starts working again.

I recently resolve a problem with the CTS signal being low : FX30S CTS Serial signal not working in latest version - IoT Gateways / FX30 - Sierra Wireless Forum

I set the MAPUART to at!mapuart=15,1 and use port /dev/ttyHS0 in my code for all serial input and output of data.

After a few days when the serial stops communicating with my device, I SSH into the modem to query the FX30S, and I find that the MAPUART is set to 1,16

Other than that, I don’t know what to look for in troubleshooting this problem.

Any thoughts on why the MAPUART setting would change by it self?

Thanks in advance!


seems the device is back to default as the setting is changed automatically

Is this related to your application?
If not running your application, will the setting being changed?

I have 1 app that runs once and calls the command “AT!MAPUART=15,1” to configure the UART initially, then it never runs again.

Other than that, I don’t make any call to the UART.

I haven’t tested to see if the FX30S resets the UART to defaults without my app running.

The funny thing is that if I reboot the FX30S, the serial begins working again. Isn’t MAPUART command not supposed to change upon reboot?


not quite sure what is changing that setting.
You might need to do some testing on stopping your application

Thanks, will do that, but first going to let it run with my app again and time how long before it changes. Might take a couples of days.