NTSC switch.

Some of you asked me for a NTSC switch to enable video source switching.

Don't ask me anything about this feature, i don't have a navigation system myself;
But here's a solution that works for several customers now, and it's real easy to build:

So you only need any NPN transistor, (I used an BC547 here) and one resistor.

Here's how you can build the extension:

	You need one NPN Transistor
	And one resistor
	Some wires
	And some shrink tubing
	Now we solder the whole circuit together
	Apply some shrink tubing to isolate the stuff
	And another bigger tub to cover the whole thing
	Connect the 2 wires (Ground and Pin 7 of the DB9 connector) You're done !! The NTSC Switch signal is the yellow wire in this case.