Description of Problem:
The genericups driver app is for "Stupid" UPSs that use "simple
signalling". They don't transmit data, they just raise/lower control
Opening the file (e.g., ttyS1) in blocking mode will block (and fail with
a timeout) because the right signals aren't present.
The attached patch is against 0.45.0 but should work for 0.44.x as well.
Created attachment 20925 [details]
open() non-blocking in open_serial_simple()
The new nut-0.45-1 in rawhide has this patch. Thanks