The connections on the rear panel of the Shamrock 500i and 750 are shown below:
Figure 4: Rear Panel Connections
Power Switch
Turn power off or on to the spectrograph.
Power Input (DC 24V)
Power input connection from the external power supply unit. The adjacent Power LED lights to indicate if the unit is 
receiving power.
Fuse
The fuse (5A) is located in a fuse holder to the right of the power input socket.
USB Control
USB connection for connection of the Shamrock to the PC, allowing control of the spectrograph through the PC.
Remote
Not applicable.
Power
Switch
Power 
Input
Fuse 
Holder
USB