I have seen both "call on" and "call at" used in English. Sometimes people just shorten it to "call"
- She called me on my cell phone.
- You should call him me at '789-263-552'.
I've also stumbled upon phrases like:
- You can call me up (at my home) in the evening.
So what is the exactly right usage?
One of my friend in America says that they use only "at" and phone number but never "on". So "on" must be British English I guess, but then should there be a number after "on" too? If so then "She called me on my cell phone." is incorrect and should be "She called my cell phone".
Where does the strange "call up (at)" come from?