Ask. It depends on the gear and how it's wired.
In the case of linear power supplies, sometimes you are lucky and it's either a switch you can slide over on the back, or internal jumpers you can move. Usually this is a little slider near the AC socket.
In the case of switching power supplies, it's automatic. You'll see them say "110-240V" or something like that in the specs.
In the case of linear power supplies, sometimes you are lucky and it's either a switch you can slide over on the back, or internal jumpers you can move. Usually this is a little slider near the AC socket.
In the case of switching power supplies, it's automatic. You'll see them say "110-240V" or something like that in the specs.