Apple PowerBook (2400c) - Manual (Page 41)

To eject a PC Card when the computer is off, do this:
m Press the right eject button to eject a PC Card from the lower slot, or press
the left eject button to eject a PC Card from the upper slot. (The eject
buttons do not work if your computer is in sleep.) If the card is not in use,
it will usually be ejected.
Use the eject buttons only when the computer is turned off. Many PC
Cards won’t eject when the button is pressed if the computer is on.
Press to eject upper PC card.
Press to eject lower PC card.
41 Using PC Cards and Additional Equipment