48VDC is the voltage used in telephone exchanges and large ISPs. This is
usually provided from a battery bank which is constantly on charge (or
some more clever arrangement) so that it is effectively a UPS. The cost
of providing the power required for a telephone exchange with mains
UPS type supplies are too high. I have seen the battery banks for an
exchange and they are huge room sized things.

Most high quality stuff has 48VDC options.

You can get 48VDC supplies but unless you already have one I would
forget it. They can be expensive and you probably don't need the hassle
in a school.

The only option option would be to get mains AC supply for the kit but
again it could end up costing a lot more than its worth.

Hope this helps,

Steve

JJ wrote:
I'm a computer software guy and I don't know much about electronics.
I need to buy a network switch for my children's school where I
volunteer as a network admin.

I found one on Ebay that meets my needs, except it says that it is the
"48V DC" version of the switch. The manufacturer of this switch sells it as
two different models, and this one is the "48V DC" version.

What does that mean? Am I going to need to get something else to get
power to it?