When I went upstairs the telephone was ringing ( the telephone was already ringing when I reached the 1st floor) When I was going upstairs the telephone rang. (the telephone started ringing while I was in my way upstairs)

did it stop ringing after u went upstairs? :P

This is simple: Ringing is present tense. Rang is past tense. So what are you talking about? If past tense: When I went up stairs, the telephone rang. If you want to make it present: The telephone was ringing when I was going up stairs.

I was going upstairs when the telephone rang. (while going up the stairs) I went upstairs and the telephone rang. (after going up the stairs) There are two different meanings here.

how about "When I went upstairs, the telephone was ringing" ?