Hey guys,
I decided to use this dock:
http://cgi.ebay.com/NEW-Dell-Latitud...2em118Q2el1247
because of the ease of taking the laptop in and out of the car, and the addition of an spdif plug. Everything was going well, until i tried to turn on the dock and it said that there was an unknown power source. I know about the third plug the propriety pin, but it was to my understanding that the laptop would still boot up, but just not charge the battery.
The barrel connector is cut from the original dell charger. The laptop works in the car without the dock. :(
Thanks

