My friend is not very experienced with electronics and computers, so he asked me how to connect his old HP Compaq nc8430 laptop to his TV. The nc8430 has an ATI Mobility Radeon X1600 with one 7-pin S-Video output and one VGA output. But his TV has neither an S-Video nor a VGA input, but it has HDMI, YPbPr, SCART and composite video. I'm used to newer computers, which have HDMI instead of S-Video. I'm also new to 7-pin S-Video, but I think I've read somewhere that the three extra pins can be for composite or component video. However, I've also read that the purpose of the three extra pins may vary from computer to computer, that's why I am asking here.
So what is the purpose of the extra pins on the nc8430?