13 Dec
2012
13 Dec
'12
1:57 p.m.
On Dec 13, 2012, at 3:55 PM, Tony Duell wrote:
That wouldn't surprise me terribly much, actually, but I've
been lucky enough to only use properly-wired S-Video cables
(each ground is supposed to be a separate signal return for
its corresponding signal. I can definitely imagine some
cheap cables tying them together at the plug ends. You'd
lose some of the video quality, but that's seldom mattered
much to unscrupulous cable manufacturers.
- Dave
Always
wondered if that was the case. I've got plenty of ADB
keyboards lacking cables and plenty of S-Video cables. So both ADB
and SVid are wired straight-through?
Yes, but there is a Gotcha.
The apple cable puts 4 separate signals on the 4 pins -- I think it's
power, grounds, serial data and the on-button. An S video cable has 2
signals (luma and chroma) and 2 grounds. It's not unheard-of for S-vido
cables to have the ground connected together, in which case they cause
ADB syutemns to think the power button is held down (IIRC).