Hello, I have a problem with the SIM800C GSM USB modem. After a few hours of trouble-free operation, it switches to unavailable status. Restarting HA will help. Can I restart only the integration or the usb device ?
Sorry for my english.
David
I expect your USB modem requiring to much current for a moment and the usb port on your HA server can’t deliver that. 
You could try to do a external power injection for your GSM modem or maybe switch to a solution which is not depended on HA directly? 