10base2 / 10baseT (again)

From: Douglas Quebbeman <dhquebbeman_at_theestopinalgroup.com>
Date: Tue Nov 28 12:58:58 2000

> > > I'm trying to think of any interface on the Mac that is in any sense
> > > 'standard'. And no, I can't think of one...
> >
> > Well, I'd posit that Apple _set_ standards instead of following them.
>
> Even when there were already perfectly good standards to use...
>
> > For example, Apple's use of a DB-25 for a SCSI port and the pinout
> > they chose has been copied widely throughout the industry.
>
> YEs, but the 50 pin SCSI standards have the advantage that there's a
> ground wire between the signal wires if you use stnadard ribbon cable.
> That's _why_ a 50 pin connector was originally chosen. The DB25 is thus
> technically inferior....

Depends on how long your cable needs to be. I've got a hard drive with
a 6-inch SCSI cable, and at lengths that short, you really don't need
the extra ground lines, unless you'be in a *really* noisy RF environment.

OTOH, if you really need to run long SCSI cables, having the extra
ground lines isn't really enough; in that sense, single-ended SCSI
is technically inferior to differential SCSI.

> > More conventionally, the serial ports follow normal pinouts, even
> > though they're electrically RS-422 instead of RS-232C.
>
> Eh? The Mac serial ports are 8 pin Mini-DIN on almost all Macs I've seen.

> That was not a standard at the time, and is only a de-facto standard now.
>
> The original Mac and Mac 512k used DE9 seiral ports, with a pinout
> different to everyone else (and yes, there _were_ 9 pin serial ports
> about when the Mac was introduced).

Until I started working here, I'd seen more 128k, 512k, and 512KE Macs
than any other models. YMMV, etc.

> > And as someone else pointed out, Mac power cords fit just about
> > any computer device from the PC era forwards.
>
> And just about any other electronic device...

Well, my old Sony reel-to-reel uses a cord that appears as if
it's compatible with my old waffle iron and coffee percolator.

;-)

-dq
Received on Tue Nov 28 2000 - 12:58:58 GMT