Performa DA-15 port pinout?

Hi,

Information about video connectors can be found, for example, via this web page.

This document could perhaps also be of interest.

Jan

Those are indeed the essential signals for a VGA or older Mac Video connection, But you have left out the absolutely crucial Horizontal Sync and its ground. Without it, the picture (if you can actually get a picture, will "rip and tear" and have wavy edges. Each scan line will not know when to start and end on the screen. This will be unwatchable.

Vertical Sync will stabilize each drawn screen (50 to 120 per second) and keep it from "Barrel Rolling". If you want to take liberties with the grounds, connecting H-Sync ground and V-Sync ground together is generally OK.

Connecting the Color grounds together is a Bad Idea. You ignore signal-pairing and signal grounding at the expense of picture quality.

The best video cables use a full-size or mini-coaxial wire for Red, Green, and Blue Video and their respective individual grounds. (e.g., Red Video inside, Red Ground to the outside of the coax.) The next-best use a twisted-pair for each color signal and its respective ground. Next-best use separate wires for each color and its respective ground. Only the very poorest quality cables EVER connect the Color grounds together.

Keep each color and its ground paired and separated from the others for best picture clarity.

Message was edited by: Grant Bennet-Alder

I am not sure what sort of display you are hooking up, but if you need crispness and color clarity, you will get better results by separating the grounds for each color (or better).

A lot of cheaper equipment can use Composite Sync, (H-Sync and V-Sync combined onto one signal) but some high end stuff may not be able to. These two signals are essentially digital, so there is not a lot of fine information that excess noise will clutter up. The first thing such a display must do is run that signal through circuitry to separate out the Syncs again, so it seems like a waste of time to try hard to combine them.

Message was edited by: Grant Bennet-Alder

The tech note on "Sense Lines" that Jan Hedlund gave you a \[blue] link to above shows the DB-15 pinouts for an older Apple monitor in the very last diagram on the last page. It shows pin 3 being used for Composite Sync OR pin 12 for Vertical Sync (if present) and Horizontal Sync (if present) on pin 15. The ground for whichever (Composite or Vertical) are on pin 11, and the ground for Horizontal Sync is on pin 14.

You will have to read the manual on your LCD TV to find out whether it has a sync-separator and can accept Composite Sync.

Message was edited by: Grant Bennet-Alder

On an Apple cable for a 1705 display, and many Mac adapters, there is no connection from the Mac Composite Sync to any VGA pin.

But you may do better with the generalized pinouts for VGA. Try this diagram:

http://pinouts.ru/Video/VGA15_pinout.shtml

a fine wire or a pin will let you "Buzz" out the internal connections in your adapters. If it has switches, the important thing to know is that only the ID bits are changed due to the switches -- the basic connectivity is wired-in. That is what the bulk of that "Sense Lines" document is all about.

Message was edited by: Grant Bennet-Alder

Message was edited by: Grant Bennet-Alder