[sdiy] AC transfo pinout

[Tom Adam]

Hi, 

I got an AC transfo but I don't know the pinout. How can I safely check
this?
It's one of these; (OK, only 4 pins on this one)
http://www.werco.nl/dbimages/t-1079630310-pi2.JPG
220V - 15V
I know I could put 2V AC on one side and look on the other, but I don't have
a 2VAC handy
I'm just not to comfortable with these things so I thought I'd ask.
Hate to fry myself.

Thanks,
Tom