I have had an Apple Macintosh home computer since 1993. I currently have an Apple Power Macintosh 7100/80AV, the Macintosh LC III I got in 1993, and a Macintosh SE I picked up along the way.
One of my pet peeves about the Macintosh is the use of non-standard connectors in their cables and connectors. I've been hunting for some of them, and actually found some standards and substitutions.
Apple did a very clever thing when designing the microphone jack for their AV series computers, although rather inconvenient to the hobbyist. The connector they use is an extended stereo headphone jack, which has four contacts including the ground as opposed to three in a regular stereo headphone jack. This was done to provide power to the Apple microphone. Unfortunately, the connector is not a standard connector and hence, not readily available.
Compared to a regular stereo jack, the one on the Apple microphone is about 5 mm longer. When you plug in a regular stereo jack, the normal three connections are made, and a 1 volt peak-to-peak signal can be captured by the computer. The extended jack also connects to the deepest connection.
The voltage level from a microphone is much lower than that, so the Apple microphone has a small amplifier powered from the jack. The deepest electrical connection provides about 5 volts DC (I don't know how much current it can supply, but I doubt it's much more than 20 milliamps).
When I did a search on the internet, I found a company called N.I.E. International in Phoenix,
Arizona that had a part number that matched the one on the
connector (590-0670). I have not contacted them yet, but if anyone does,
let me know.
In a moment of divine intervention, Apple chose the same connector for their ADB port as is in use with Super-VHS. Both have four conductors and an index key spaced the same, but the alignment key in the shield is "outdented" for the S-VHS connector (on the left) and indented for the ADB connector (on the right). Most jacks seem to support either alignment key.
In short, if you're looking to replace or extend an ADB cable, you can
use a Super-VHS cable in its place. Radio Shack has them, as well as
most other audio/video shops. Cost wise, the two cables should be
Last updated 1997-Feb-16
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