What kind of outlet is this?

http://i4.photobucket.com/albums/y12...isc/outlet.jpg

Let's see now.

A vertical small prong (hot) and sideways large prong (neutral) would
signify 120V / 20A. On the receptacle the sideways opening gets a vertical
aspect for a combined T shape so it can accept a common 120V / 15A plug as
well.

On the other hand the small opening being sideways while the large is
vertical signifys a 208-240V / 20A outlet and the receptacle's vertical
side is also given a horizontal aspect for a combined T shape so it can
accept the rather rare 208-240V / 15A plug with two flat prongs sideways.

The outlet shown is obviously to some ancient standard. Looks like it will
accept anything...except a ground pin. LOL.