Power cycle USB or ethernet modem

I have several Gli routers connected to USB modem.
Modems idle periodically and need to be power cycled to enable data again.
I have script to reboot Gli router if ping heartbeat fail, but reboot Gli router does not cut power to USB modem.
Is there command to cut USB power without physically disconnect cable?

There is USB power cycle. No need to reboot.

Taking MT300N-V2 for example

echo 0> /sys/class/leds/gl-mt300n-v2:green:power/brightness
sleep 1
echo 1> /sys/class/leds/gl-mt300n-v2:green:power/brightness

I do not see that in the units I look at.
Some do not even have class/leds or /gpio folders.
What is the path directory for these device: