iPT's have a new security software that looks for a special chip in docking stations, and when it can't find it, which applies to any dock except for the Apple Universal Dock, (not to be confused with the iPod Universal Dock made back in 2004) will not work with the iPT for displaying Video.
The charging has also changed to the 5v circuit instead of the firewire 12v circuit that was used in earlier docking stations, including all of Apple older docking stations, which is now required to charge the iPTs.
This is why so many people here are very upset with Apple, in that most of the older cables and docks no longer work with the new iPT's. Even the new component and composite AV cables have security chips in them, so that the iPT will send video out of the docking port.
The reason for the chips is so that non licensed companies products will not work with the iPT's. They must include this new chip for the cables and docks to work. Therefore those companies must pay Apple a license fee for the chips.
As for the charging circuit now used, Apple warned vendors a couple of years ago that this change was coming and they needed to make the charging circuit change in there products. Seems many vendors of accessories ignored this warning.
