Mac to Bernoulli Cable

From: Richard Erlacher <edick_at_idcomm.com>
Date: Tue Mar 21 10:06:29 2000

The Bernoulli drives I have are all more or less the same, irrespective of
their generation. The PC interface card.cable uses a 37-pin (DC37) sub-D
connector and that's essentially a SCSI cable with the unused conductors
omitted. This makes for fewer conductors in the cable, but, if you look
inside the drive, the attachment to the controller is via a 50-conductor
ribbon cable, an adapter to which is attached to the bulkead at the rear of
the box. The interconnections between the drives are 50-conductor ribbon,
and, depending on the generation of the hardware, but for most of the 10 MB
8" drives, the controller is generally a separate card to which the drives
attached. It is more or less standard SCSI, though it doesn't work well
with other adapters or with ASPI drivers under DOS. I doubt the MAC uses
different internal hardware or cabling, though the BERNOULLI drives hung on
for a longer time in the MAC environment because of the MAC's smaller size
requirement. I have an old Xebec drive which uses precisely the same
cabling arrangement as the various BERNOULLI systems I have, and it also is
terminated at the drive/controller end in a 50-pin cable from its external
37-pin version. One of the BERNOULLI arrangements I have came with an
adapter to the more or less standard Amphenol (looks like a big Centronics)
50-conductor "Blue-Ribbon" connectors. This works because the controller
board on the Bernoulli's controller has soldered-in terminations.

I'd speculate that if you open a box and attach a typical SCSI-1
device-attachment cable not necesarily with both of the female connectors
attached, it will work with standard SCSI cabling. You'll have to make/buy
whatever the necesssary adapter from your MAC to the "SCSI-1" cable happens
to be, however.

Dick

-----Original Message-----
From: Bill Pechter <pechter_at_pechter.dyndns.org>
To: classiccmp_at_classiccmp.org <classiccmp_at_classiccmp.org>
Date: Tuesday, March 21, 2000 7:45 AM
Subject: Re: Mac to Bernoulli Cable


>> > I am looking for a cable to attach a Mac SE (DB25?) to an 8"
>> >Bernoulli Drive (Amphenol?) John Sowden
>>
>> Chances are I have it, but I don't know what it is. The SE SCSI port is
>> DB25F (so the cable is DB25M), explain the other connector in more
detail.
>> The three common ends are;
>>
>> DB25M, most older mac SCSI devices.
>> Centrontics50M, most SCSI devices.
>> HD (high density) C50M, compaq and some sony.
>>
>
>Anyone know anything about Centronics to DB50 pin typecables having
problems
>with termination or termpower on Suns...
>
>Was there multiple versions of the 50 pin pinout in the early days.
>
>Symptoms -- hung scsi bus on Sparcstations... inability to probe SCSI
>when used.
>
>Bill
Received on Tue Mar 21 2000 - 10:06:29 GMT

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