on the other end, at the other end, on the other side, at the other side
Are they full interchangeable?
As far as I know, some contexts prefer one over the others.
In the context of phone : The person on the other end (not at the other end or on the other side)
talking about a city: On/at the other side (not end!)
Please help me distinguish their usage. It doesn't have to be thorough. I just need something to give me an idea, a foundation for me to build on.
Thanks