Questions on SCSI device interfacing...

[Paul Vixie]

In article <704 at hodge.UUCP> rusty at hodge.UUCP (Rusty Hodge) writes:
# A raw SCSI drive usually has a 50-pin header connection.  The standard SCSI
# connection is a 50-pin Centronics.  The Macintosh folks use a DB-25.  Don't
# ask me to explain, but it works.

The 50-pin ribbon cables have ground on every other pin, which is common.  So
there are only 25 pins worth keeping if you don't care about horizontal
shielding between each pair of pins.

The Apple DB25 setup has a shield around all 25 pins, which is connected, at
the Centronics-to-DB25 connection, to the bus-bar of 25 grounds found in the
50-pin ribbon cable.

It sounds flinky but it works.
-- 
Paul Vixie
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