This works too:
shell_command:
test_lounge_ac: 'curl -k "http://10.1.1.9/r?d=4&t=21&f=176&a=0&s=1"'
I can work with that.
I’d still be interested to know why I couldn’t get the restful command to work if anyone knows.
Edit: I just realised HA was returning error 401 (unauthorized) not 404 (not found) for the restful command. Which explains why curl with -k option (insecure) works. Why the restful command is trying to make a secure connection to an http address on the other hand is a mystery.
It’s all academic now as I have realised I can do this a lot simpler with shell_command.