12 Dec
1998
12 Dec
'98
5:36 p.m.
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.
Joe
12 Dec
12 Dec
4:03 p.m.
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.
<<<John>>>
13 Dec
13 Dec
3:01 a.m.
John,
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?
Joe
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.
<<<John>>>
11:33 a.m.
John,
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?
Joe
There's a SCSI card for the 3b2 series... I think the 3b2600 was the
first machine that built in the scsi as standard... The 400 and 310
all used MFM drives standard but had a SCSI option...
Bill
9510
days inactive
9510
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jruschme＠hiway1.exit109.com -
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