har du prøvde å slå det av og på igjen?
"Hello, IT, have you tried turning it off and on again?"
That was also my first association :-)
Could this sentence be translated as "you have to restart the phone."
I was thinking the same thing. Restarting a phone is turning it off and turning it back on again. Is there a separate word for "restart" or what?
You can use either "restart" or "omstart" for that (they work as nouns and verbs), "å starte på nytt" is also quite common in addition to "å slå av og på (igjen)".
Do 'av' can mean both off and on...?
In this context, it means "off", but often prepositions can form part of phrasal verbs that do not translate directly, which is why they end up with a myriad possible translations.
Ancient wisdom, always works
It sounds like you're turning off a road first XD
We would say;
One must turn the telephone on and off repeatedly.
Man må slår telefonen på og av mange ganger.
I understand this is not the lesson.