Philo never ceases to amaze me… This time he has done it again…    Quoted from Philo’s post on NXTasy forums:

 ”This special cable allows you to power external devices such as a a motor multiplexer or a wireless camera from your NXT. No need for external bulky battery box! (if your current consumption is low enough, 800mA max). Though plugged into NXT port A, it lets you use the NXT motor connected there almost normally.”

More information:  http://philohome.com/nxtpwr/pwr.htm