Based on the names of most of the signals, I'd say the 50-pin host interface
connector is for an early version of SASI or SCSI but done tenuously enough
that there was margin for going with a standard when one evolved. The
manual in my possession is dated January 16. 1980. They didn't have a
standard then, and, in fact SCSI was still pretty much of an illusion at the
time. I'd guess it's a safe bet that this one will work with SASI hardware
or even with some SCSI hardware. I doubt that it will work with most
state-machine-driven interface devices, since some of the signals are not
present, and, frankly, this interface is far enough off the mark that it
probably needs a programmed I/O sequence to handle it.
Dick
-----Original Message-----
From: allisonp_at_world.std.com <allisonp_at_world.std.com>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Wednesday, December 15, 1999 7:01 AM
Subject: Re: DTC 520A - SASI or SCSI?
>
>Ok,
>
>Likely that is something else. I'd expect the 34pin to be floppy and
>maybe MFM hard disk.
>
>The 50pin could be... QIC02, QIC24 or maybe the old Hard disk interface
>used for the 8" hard disks (SMD?) like the SA4000.
>
>!983 SCSI ws likely SASI, but many tapes and disks used a 50pin parallel
>like interface back then too.
>
>Allison
>
>
>On Tue, 14 Dec 1999, Ethan Dicks wrote:
>
>>
>> Going through a box of disk interface cards, I ran across a couple of
these
>> DTC 520As. Cursory examination shows a 50-pin connector (J4) with two
>> termination resistors (220/330), two 20-pin connectors (J2, J3) which are
>> presumably analog data for two ST506 drives and two 34-pin connectors (J1
>> and J9). I would expect that J1 is the control cable that goes with J2
and
>> J3. I suspect that J9 is for floppies. The major chips are two 8255s,
one
>> 8085, one DTC-037, one NEC D765, one FDC-043, one DTC MSA 2827G, an AMD
P8353,
>> and an AMD AM9517. There are several chips with the numbers covered by
type-
>> written numbers, PALs and ROMs, no doubt.
>>
>> There are 8 LEDs in a row by the power connector and an 8-position DIP
switch.
>>
>> >From the date codes, it appears to have been made near the end of 1983.
>>
>> Can anyone shed any additional light on this device? Knowing what this
was
>> expecting to hook up to and how to set the DIP switches would be a great
help.
>>
>> Many thanks,
>>
>> -ethan
>>
>>
>>
>> =====
>> Infinet has been sold. The domain is going away in February.
>> Please send all replies to
>>
>> erd_at_iname.com
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>
Received on Wed Dec 15 1999 - 13:30:23 GMT