Empower connector for airline laptop power

I bought an Empower adapter with a male connector on one end and a
female cigarette lighter connector on the other (for my 12-20 volt
laptop power connector that normally gets power from a cigarette
lighter). The male (Empower adapter) connector has 4 pins: 2 large
ones and 2 small ones. Using an ohmmeter, I deduced that the 2 large
pins are the ones that the connector thinks will have 12-15 volts. Not
sure what the 2 smaller pins do (a switch?). If you're having trouble
knowing what the connectors look like, have a look at
http://www.magellans.com/store/additional_images/EA270?Args=','no',400,575

Well, imagine my disappointment when I found that no power made it to
my laptop. I'm pretty sure that:

1) Power was coming out of the airline armrest: armrest light was on,
others had power. I tried 4 different seats in 2 airliners--same
result.

2) My 12-20 volt power connector works OK. It has lights that come on
when it is getting power. No lights on the airliner, lights present
when plugged into my car cigarette lighter.

Does anyone know how these adapters are supposed to work? I'm trying
to figure out if I have a faulty Empower adapter or whether there is
some other problem. One thing that I did notice is that the 2 smaller
Empower pins are not as extended as the larger ones (the ones that
presumably carry the power). I wonder if this is the norm. If anyone
has a circuit diagram, I'd be interested in seeing it.

If you reply, please copy me at:



TIA

Lee Elson