the simplest answer i can give is it supplies 48vdc after it is rectified and power up whatever device is connected to that.
since you are interested with this supply voltage, are you trying to build one? you can make a single supply (0v-48v) or a dual supply (48v-0v-48v) depending on your need.
The simplest way is with a transformer and a rectifier, with perhaps some filtering/smoothing capacitors. Is the load you intend to power with this supply very voltage sensitive? Do you need to have any regulation in your supply?
okay, so how are gonna rectify your secondary ac, is it in a half wave, full wave, or bridge manner. you see these are factors you have to consider because they entail different factors to be used in using the formulas in making power transformer. i could give you the various formulas involve in making EI core power transformer.
but the easy way is just buy it.
if you dont have a winding tool you just have to hand wind it and i tell it is pretty hard. i use to do that and was forced to buy a rewinding tool.