If your wireless combo is USB+PS/2
then it should have 1 USB + 1 PS/2
if you are using it on USB, then you will only require to plug in the USB
and both keyboard and mouse will be connected to the same Receiver.
if you are running on a PS/2 port , then you will need both Purple color (keyboard)
PS/2 to go into keyboard PS/2 port and Green Color (mouse) PS/2 to go into
mouse PS/2 port