Yeah sort of - although I kind of meant less about being available to drop everything and work on something immediately vs. just being around to answer questions perhaps that may or may not be urgent.
That's still on call, though. If I'm expected to answer the phone and answer work questions, I can't be hiking in an area with bad cell coverage. I can't be drunk. I can't be in a theater. Perhaps I can't be on a bike ride if I need to have a laptop nearby. On and on - if it's a restriction on my life during non work hours, it's on call.
i think it's still different. being on call means i must be able to work during that time.
being reachable means that you can pass on your problem, and i'll acknowledge it so that we can together decide what the best next step. sometimes we can solve the problem, sometimes we can find someone else who can also help, and sometimes we need to delay working on the problem and reschedule it for another time. but at least then it's scheduled. on a few occasions i am not reachable at all. but that doesn't happen often.
in other words being on call means always to solve the problem immideately, whereas being reachable means i have the option to say no.
but it's different from being on-call. i understand that in many places, on-call requires the same payment as regular work hours for the whole period, not just for the hours worked.
and i don't feel it's an intrusion if being available is optional and not required.
it's essentially how every freelancer works. they are available during business hours. but they don't get paid if they don't get called for work by a client.