On OpenWRT devices, we use QUECTEL EC25-E GSM Module, sometimes internet is disconnecting, when it disconnect we send AT+CFUN=1,1 to GSM Modem.
Before send command devices are;
crw------- 1 root root 188, 0 Jun 27 15:35 /dev/ttyUSB0
crw------- 1 root root 188, 1 Jun 27 15:35 /dev/ttyUSB1
crw------- 1 root root 188, 2 Jun 27 15:35 /dev/ttyUSB2
crw------- 1 root root 188, 3 Jun 27 15:35 /dev/ttyUSB3
After I send command
crw------- 1 root root 188, 0 Jun 27 15:39 /dev/ttyUSB0
crw------- 1 root root 188, 2 Jun 27 17:46 /dev/ttyUSB2
crw------- 1 root root 188, 3 Jun 27 15:39 /dev/ttyUSB3
crw------- 1 root root 188, 4 Jun 27 15:39 /dev/ttyUSB4
devices are changing, it results internet cannot be connected.
We use 100 Module per month, but we could not solve it yet. If fd is using this port it happens. But we even do not use that fd but it still changes its port.
Is there a way to prevent?