Anyone know what this is for?: AT&T ext SCSI drive

From: Joe <>
Date: Sun Dec 13 11:01:49 1998


  I think you may be right. There's a co-axial connector on the 3B2 that's
exactly the same as the one on the drive and there's no power switch on the
drive. I KNEW I had seen those connectors somewhere before. I have a couple
of 3B2s but I don't have any docs for them and I've never fired them up.
The drive has the standard Amphenol SCSI connector. There's no connector
like that on the 3B2 only a couple of uunmarked ribbon cable connectors.
Does the drive connect to one of them or is there a card for the 3B2 that
has a SCSI port? If it does connect to one of the ribbon cable connectors,
do you have a diagram of the cable so I could make one?


At 01:03 AM 12/13/98 -0500, you wrote:
>> I found this while digging through a surplus store. AT&T external SCSI
>> drive model DM/300S. It's a white metal box about 11" square and 4" high.
>> Does anyone know what machine/system it's for or the specs for it? It has
>> two round co-axial connectors on the back marked "Power" and "Control".
>> Anyone know what they're for? It has a socket for an AC power cord so the
>> "Power" connection isn't for powering the drive.
>Sounds suspiciously like it's for a 3B2.
>The 3B2 used an interesting daisy-chained soft-power scheme. When the main
>system was powered up, it would put out 5V on a coax port on the back. The
>5v would close a relay on the power supply of the expansion box (in lieu
>of a switch) and turn on power to the expansion box.
>I'm guessing here, but I assume that one of the ports is the 5v in and the
>other would output 54v to power up the next peripheral in line.
Received on Sun Dec 13 1998 - 11:01:49 GMT

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:30:49 BST