Ask HN: Help for 24/7 on rotation/call contract for employee (me)

sorry for the throw away account. I'm a junior-ish sys admin with 3 years experience and I've been interviewing with an IT operations support company where an ex-colleague of mine works. I like the company, the people and the work they do but this would be my first experience of rotation/on call. I know I will have to wait for their offer and then judge but I'd like to be prepared... too bad I have no idea what's "normal" and what's not!! I'm in the UK (London) and it would be great to have any feedback/idea on: - what kind of contract should I expect? - what things should I negotiate on (harder than usual)? I know they are flexible and happy to consider different arrangements for different people but, as mentioned, I don't know what's normal - do you get paid a sort of normal salary but don't work during the day if you get woken up the night before? or do you get paid more when you are woken up? Anything really! Thanks a lot for any input