I use a WP7607 with Legato 18.10.2 on a custom board with an external 5V power supply.
I create an SSH connection, and use the cm tool to switch on the radio and create a data connection.
The system gets registered to the home network and uses UTMS by default.
When I disconnect the antenna from the target board, after a while, all the Legato services get terminated and even the SSH connection gets disconnected.
l see following line in the logs:
le_mrc.c SignalStrengthIndHandlerFunc() 875 SignalStrengthIndHandler called with RAT.1 and ss.-91
So, this means that the system switched automatically from RAT UMTS(2) to RAT GSM(1), and then stopped working.
I can reproduce the same behaviour (apps terminated and SSH disconnected) when I execute the steps below:
- create a data connection using UMTS via cm tool (antenna connected to the target board)
- disconnect the antenna
- force the RAT into GSM : cm radio rat GSM
The system immediately terminates all services and the SSH connection gets lost
Could this be a power saving feature?
Why is the RAT going from UMTS to GSM when the signal gets too weak?
How can I avoid that the system stops working?