(...) I thought it might work like that, you can't see the top of the half 9v connector in the picture of course. I guess it's cheaper, one product/two functions. (17 years ago, 27-Dec-07, to lugnet.technic)
(...) This shape also enforce a PF rule: power source is always available on top of PF connector, while power input is always done from bottom of connector (similarly to mains power distribution sockets/plugs). Philo (17 years ago, 27-Dec-07, to lugnet.technic)
