A PowerBook G3 Series (Bronze keyboard) does not go into sleep mode when IrDA is selected in the AppleTalk control panel.

This is normal operation when IrDA is selected. The computer must be awake to monitor the infrared port for incoming data, similar to telling the modem to wait for an incoming call.

You can force the computer to enter sleep mode through the Special menu or by pressing the Power key and selecting Sleep from the dialog box presented.