Boeing 727 APU Fire Handle

[arff]

Hello;

In the left main gear wheel well of the B727, the external APU fire handle is located. Next to it is the control switch for discharging the halon bottles. My question is: does the fire handle (also known as T-handle) just cut off the fuel to the APU or does it cut off other system like APU air Intake and APU electrical system?

Thanks.