[RndTbl] SCSI cable length

Hartmut W Sager hwsager at marityme.net
Fri Jul 3 19:48:08 CDT 2015


> I'm a big SCSI guy, but ...

I too am an old SCSI fan, but my interest started to wane when so many SCSI
signalling standards and connectors began to proliferate together with SCSI
moving totally into the high-end server realm and away from "ordinary"
peripherals.  Oh, and then there was that "termination power" headache
(usually selected/deselected by jumpers).

> The device has a standard dense 50-pin 2-row connector.  I thought at
first that meant for sure LVD, but now I'm thinking it just means ultra.

It doesn't even mean "ultra", let alone HVD/LVD.  That connector became the
norm during the single-ended classic SCSI 2 generation - to my great
chagrin, since the Centronics 50-pin connector was so much better.

> Is there a way to know what signalling this device uses based just on the
connector?

No, but:

> I checked all available interent specs, incl the original manual, for the
device and *nothing* specifies anything other than "SCSI".

Since the original manual (lucky you to have that!) doesn't specify
anything other than "SCSI", it is a near certainty that this isn't LVD or
HVD, but simply good old single-ended classic SCSI (of at least SCSI 2
generation).  It probably isn't "ultra" either, especially if it's a
scanner or CD drive or similar slow device rather than a hard drive.

Hartmut W Sager - Tel +1-204-339-8331, +1-204-515-1701, +1-204-515-1700


On 3 July 2015 at 16:06, Trevor Cordes <trevor at tecnopolis.ca> wrote:

> I have an external SCSI device that I'd like to plug in on a 10-15' cable.
> The device has a standard dense 50-pin 2-row connector.  I thought at
> first that meant for sure LVD, but now I'm thinking it just means ultra.
> I need LVD to get over 1.5M cable length, according to spec.  LVD lets me
> go to 12M it appears.  If it's just ultra then I'm SOL, I guess.
>
> Is there a way to know what signalling this device uses based just on the
> connector?  I checked all available interent specs, incl the original
> manual, for the device and *nothing* specifies anything other than "SCSI".
>
> I'm a big SCSI guy, but my memory on the subject is starting to get
> hazy due to disuse...
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