8 Dec
2016
8 Dec
'16
6:18 a.m.
Hi,
recently I acquired a 1980s Typewriter, a Brother TC-600.
While not exactly a classic computer, this typewriter was often used as a
low cost printing terminal (aka teletype).
It has a serial interface and I was able to connect it to my PC. I can SEND
characters and text files to a terminal program. However I have not found
out how to receive something back. Ideally it should print out what the host
sends. On the internet I found a manual for the Brother EP-44 which is
similar, but not identical.
Does someone have a manual for the TC-600?
Thanks,
Martin
I'm an electronics noob, but do you mean a threshold of 1.5V, as with
DS8641?
I'm not a noob. I'm an engineer from the the realm of DEC engineering.
I also forget the 74LS14 hex inverter with hysteresis which has a
threshold about 1.5V
depending on whos datasheet you believe.
Bottom line is the older parts has a low Vih and a high Vil with a
resulting narrow noise immunity.
Increasing the Vih helps this and the driver/bus combo can support it.
The yabut is if the drivers
have leakage then attaining Vih on the bus is problematic as the leakage
was a undesired pull down.
The 8xxx parts used were screened for low leakage with output is in the
high state (open as they
are open collector). The bus loads assert the Voltage high state and
that is above 2.3V so the only
limiting factor then is excessive capacitive loading which smears pulsed
by RC time constant. The
other issue with slow edges is where the edge really is and that adds
uncertainty to timing. All
of those things were allowed for in the design of the bus.
The voltage your hung up about was tested to insure it was never lower
than that or the noise
immunity was terrible. Its companion was was that the saturated device
in the package could
also achieve the limit or less or a low voltage at the rated current, at
that time (late 60s early 70s)
this was a hard parameter to control.
The bottom lime is the better the logic high voltage and logic low
voltages achieved the greater
noise immunity. Adding hysteresis insure that a hig is high and a low
is low and not some random
analog voltage inbetween (or oscillation!).
As to any slew rate testing the issue was that devices that could sink
the needed current were also
slow as sludge and had to be tested to insure they were fast enough not
that they would have a
slow propagation time and switching speed as that was also a undesired
in systems where fast
is important. Bottom line is the datasheet and purchase spec was to
insure the part worked to or
better than expected rather than implying magical properties.
Allison
> I'm referring to this part of October's thread:
> http://www.classiccmp.org/pipermail/cctalk/2016-October/028871.html
>
>
> --Toby
>
>
>> important for large systems with multiple bus segments. That was
>> particularly important for large Unibus systems, but even Qbus with only
------------------------------
Message: 3
Date: Tue, 06 Dec 2016 14:27:22 -0500
From: allison <ajp166 at verizon.net>
To: "General Discussion: On-Topic Posts" <cctech at classiccmp.org>
Subject: Re: Intel C1101A
Message-ID: <33d486b9-62b2-a536-82d5-c9b61c41c71e at verizon.net>
Content-Type: text/plain; charset=utf-8; format=flowed
On 12/6/16 11:46 AM, Brad H wrote:
> I kind of thought that might be a possibility. I might just let things lie
for a
-----Urspr?ngliche Nachricht-----
Von: cctalk [mailto:cctalk-bounces at classiccmp.org] Im Auftrag von cctalk-
request at classiccmp.org
Gesendet: Mittwoch, 7. Dezember 2016 19:00
An: cctalk at classiccmp.org
Betreff: cctalk Digest, Vol 30, Issue 7
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Today's Topics:
1. Re: Double Buffer RK11-C (Fritz Mueller)
2. Re: UNIBUS/QBUS interface chips Was: Re: MEM11 update (allison)
3. Re: Intel C1101A (allison)
4. Re: Double Buffer RK11-C (Paul Koning)
5. Could somebody please help me identify this board? (Chris Pye)
6. Re: Could somebody please help me identify this board? (Jon Elson)
7. Re: Could somebody please help me identify this board? (Chris Pye)
8. Miniscribe 6053 HD PCB needed (Mike Stein)
9. Re: Could somebody please help me identify this board?
(Mike van Bokhoven)
10. Re: Could somebody please help me identify this board?
(Eric Smith)
11. Have lunch with Lee Felsenstein (Evan Koblentz)
12. Wanted: Terminator for an RL02 (Tom Moss)
----------------------------------------------------------------------
Message: 1
Date: Tue, 6 Dec 2016 11:56:38 -0800
From: Fritz Mueller <fritzm at fritzm.org>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Re: Double Buffer RK11-C
Message-ID: <DF227289-9352-4646-8339-72E2640AF202 at fritzm.org>
Content-Type: text/plain; charset=utf-8
> On Dec 6, 2016, at 7:51 AM, Noel Chiappa <jnc at mercury.lcs.mit.edu>
wrote:
>
> [data fetch] can't be off-loaded onto a separate interface unit, as it
needs
access to
actually
register contents held in the CPU.
Yeah, it?s pretty interesting! My guess would be that it was a separate
register/command oriented interface, sitting on the Unibus, and didn?t interface directly with the 11/20 CPU? Such an
interface could limit the
instructions ?fed? to the FPU to those accessing its internal registers,
etc. But
who knows? :-)
I?ve gotten quite deep into the design of the FP11-B and associated KB11-A
interfacing during my debug (which is how I noticed all the 11/20 refs in
the
docs, circuitry, and microcode), but I?m pretty
ignorant of the 11/20
having
never worked on one.
> I wouldn't be surprised if there's some microcode in the KB11 to support
those
memory operations.
Yes, there certainly is ? quite a bit of it actually. The are F/CLASS
branches off
all
three of the A, B, and C forks.
?FritzM.
------------------------------
Message: 2
Date: Tue, 06 Dec 2016 14:24:21 -0500
From: allison <ajp166 at verizon.net>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Re: UNIBUS/QBUS interface chips Was: Re: MEM11 update
Message-ID: <8d451f35-e495-5feb-86b4-e0b0992ed2d7 at verizon.net>
Content-Type: text/plain; charset=utf-8; format=flowed
On 12/6/16 10:05 AM, Toby Thain wrote:
> On 2016-12-06 1:34 AM, Eric Smith wrote:
>> On Mon, Dec 5, 2016 at 6:53 PM, allison <ajp166 at verizon.net> wrote:
>>
>>> A bunch of us old digits (former dec engineers) got together and were
>>> talking
>>> about old systems and the thing that stood out is a general dislike
for
>>> having
>>> to use the limited set of bus interface chips when there were newer
>>> parts. It
>>> was a internal mandate not something that was better than could be
had.
The
logic was the parts were known, the vendors vetted for quality and
reliability
and when you use hundreds of thousands to millions of a part like bus
interface
and ram quality is a critical thing. Were they special, a flat no.
I don't fully agree. The receivers (and transceivers) had a threshold
voltage that is not available with modern parts, and that actually was >> two bus segments can get finicky when heavily
loaded.
>>
>> DEC could easily have made custom interface ICs if they had needed
them.
AFAIK, *no* current production interface ICs have the right
threshold. It's
hard to meet the spec without using either NOS parts or comparators.
It would certainly be possible to build a functionally equivalent bus
with
modern interface ICs, and it might have significantly better
performance,
but it wouldn't be compatible with the legacy systems.
while.. I was concerned about stock disappearing,
didn't think about price
tripling. Not sure I want to spend $1400 for 1K of RAM on a clone. :)
"hits"
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Corey
Cohen
Sent: Tuesday, December 6, 2016 4:27 AM
To: General Discussion: On-Topic Posts <cctech at classiccmp.org>
Cc: General Discussion: On-Topic and Off-Topic Posts
<cctalk at
classiccmp.org>
> Subject: Re: Intel C1101A
>
> I do notice these "schlock" IC sellers actually raise the price the more
they get on an item. So your shopping around will
actually make the price
worse
and my even cause your earlier vendors to raise their
price when you
finally do
place an order.
>
> corey cohen
> u??o? ???o?
>
>> On Dec 4, 2016, at 9:00 PM, jim stephens <jwsmail at jwsss.com> wrote:
>>
>>
>>
>>> On 12/4/2016 3:29 PM, Brad H wrote:
>>> The supplier (a different one from the one I first used) that quoted
>>> me on C1101A for the second round sent me a picture.. exact same
'lot'
or
'job'
>>> number as the ones I have. So perhaps even that may not be
meaningful?
>>> What are the odds I'd hit the exact
same dates from two different
suppliers?
>>>
>>> I'm thinking it's*fairly* safe to assume white ceramic is pre-76,
at
>>> least.. but yeah.. might be impossible to ever really know. I'm just
>>> wondering why the price jumped to $40+ each all of a sudden!
>> Brad,
>> a very large number of schlock IC sellers all communicate with each
other.
They all have a continuous stream of wants or needs
that they exchange.
but
they make their own prices. The probability is that
you may have hit the
original
stocking guy with your first query. Querying any
others will result in
them
looking at the wants that others shared, or buys, and
he saw someone else
had
it and quoted you the same info.
>>
>> I know this happens as I know two guys who trade in all manner of stock
all
the time like this and have for 35 to 40 years.
wrote:
>
> thanks
> Jim
Considering the first 1101s I ever bought in the early 70s were around
12-14$ each in small volumes (24-48).
By the mid 1975s they had dropped to a buck or so as there were faster
and denser parts. But then the first 2102s
cost me about 14$ in early 74 so that was the way it was.
Allison
------------------------------
Message: 4
Date: Tue, 6 Dec 2016 16:13:43 -0500
From: Paul Koning <paulkoning at comcast.net>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Re: Double Buffer RK11-C
Message-ID: <E3C0D8A7-1B50-4877-97E1-7E930FDD07A7 at comcast.net>
Content-Type: text/plain; charset=utf-8
> On Dec 6, 2016, at 2:56 PM, Fritz Mueller <fritzm at fritzm.org> wrote:
>
>
>> On Dec 6, 2016, at 7:51 AM, Noel Chiappa <jnc at mercury.lcs.mit.edu>
>>
>> [data fetch] can't be off-loaded onto a separate interface unit, as it
needs
access to
register/command oriented interface, sitting on the Unibus, and didn?t
actually
register
contents held in the CPU.
Yeah, it?s pretty interesting! My guess would be that it was a separate interface directly with the 11/20 CPU? Such an
interface could limit the
instructions ?fed? to the FPU to those accessing its internal registers,
etc. But
who knows? :-)
I don't know anything of a DEC product along those lines, but a college
classmate of mine (Bill Black, Lawrence Univ. class of 1975) built a
floating
point
coprocessor for our PDP11/20 that was a Unibus
peripheral. I helped with
the
software interface. The device had 4 registers, two
for source and two
for
second source and result. They appeared at several
different bus
addresses;
you'd select the operation to perform based on
which address you used.
The
device would start when the 4 source words had been
loaded, then a read
cycle
of the result register would simply be held off until
the operation was
done
(since it would complete well within the SSYNC
timeout).
The implementation took, if I remember right, one hex-sized wire wrap
board.
paul
------------------------------
Message: 5
Date: Wed, 7 Dec 2016 10:57:03 +1000
From: Chris Pye <pye at mactec.com.au>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Could somebody please help me identify this board?
Message-ID: <BE8ACBED-16AE-4C35-B519-33E5DF0FFEF7 at mactec.com.au>
Content-Type: text/plain; charset=utf-8
I?m moving my collection and found this board amongst some others.
https://drive.google.com/open?id=0B0m4VYF4tIU5aXJMSHBwUDJMUWM
<https://drive.google.com/open?id=0B0m4VYF4tIU5aXJMSHBwUDJMUWM>
Cheers,
Chris
------------------------------
Message: 6
Date: Tue, 06 Dec 2016 20:32:10 -0600
From: Jon Elson <jonelson126 at gmail.com>
To: General Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Subject: Re: Could somebody please help me identify this board?
Message-ID: <584774AA.2050400 at pico-systems.com>
Content-Type: text/plain; charset=utf-8; format=flowed
On 12/06/2016 06:57 PM, Chris Pye wrote:
on
it.
I?m moving my collection and found this board
amongst some others.
https://drive.google.com/open?id=0B0m4VYF4tIU5aXJMSHBwUDJMUWM
<https://drive.google.com/open?id=0B0m4VYF4tIU5aXJMSHBwUDJMUWM>
Cheers,
Chris
It appears to be an extended-length Multibus II board with 2 8-bit DACs
on it. Output for an XY scope?
Jon
------------------------------
Message: 7
Date: Wed, 7 Dec 2016 12:40:49 +1000
From: Chris Pye <pye at mactec.com.au>
To: elson at pico-systems.com, "General Discussion: On-Topic and
Off-Topic Posts" <cctalk at classiccmp.org>
Subject: Re: Could somebody please help me identify this board?
Message-ID: <00BE5D7E-6202-4D62-851D-FAA884636B7A at mactec.com.au>
Content-Type: text/plain; charset=utf-8
On 7 Dec 2016, at 12:32 pm, Jon Elson
<jonelson126 at gmail.com> wrote:
On 12/06/2016 06:57 PM, Chris Pye wrote:
> I?m moving my collection and found this board amongst some others.
>
> https://drive.google.com/open?id=0B0m4VYF4tIU5aXJMSHBwUDJMUWM
<https://drive.google.com/open?id=0B0m4VYF4tIU5aXJMSHBwUDJMUWM>
>>
>> Cheers,
>> Chris
> It appears to be an extended-length Multibus II board with 2 8-bit DACs Output for an XY scope?
Brisbane
Jon
Thanks Jon
If anybody wants it, they can have it for cost of postage. I am in Australia, so it?s probably going to be costly outside
AU..
------------------------------
Message: 8
Date: Tue, 6 Dec 2016 21:58:24 -0500
From: "Mike Stein" <mhs.stein at gmail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Miniscribe 6053 HD PCB needed
Message-ID: <074CFFA13AFF454581BCC3E1EEEC5306 at 310e2>
Content-Type: text/plain; charset="iso-8859-1"
Hi all,
I accidentally dropped something on a Miniscribe 6053 44MB HD and cracked
the board; looks pretty dense and tricky to repair so I'm hoping that
there's a
kind soul out there somewhere who happens to have a
6053 doorstop and can
spare the circuit board for a good cause?
Removing the board shouldn't impair the door-stopping capability in any
way...
Mike (in Toronto)
------------------------------
Message: 9
Date: Wed, 7 Dec 2016 18:18:36 +1300
From: Mike van Bokhoven <mike at fenz.net>
To: cctalk at classiccmp.org
Subject: Re: Could somebody please help me identify this board?
Message-ID: <ed5f1e6c-2028-d7dc-88ea-5090430b2e8b at fenz.net>
Content-Type: text/plain; charset=utf-8; format=flowed
On 7/12/2016 1:57 p.m., Chris Pye wrote:
on
I?m moving my collection and found this board
amongst some others.
https://drive.google.com/open?id=0B0m4VYF4tIU5aXJMSHBwUDJMUWM
<https://drive.google.com/open?id=0B0m4VYF4tIU5aXJMSHBwUDJMUWM>
Cheers,
Chris
It's a Compugraphics board of some sort, I think. Couple of AD or DAs,
etc. I know nothing about these, just recognised the logo.
Cheers - Mike
------------------------------
Message: 10
Date: Tue, 6 Dec 2016 22:57:08 -0700
From: Eric Smith <spacewar at gmail.com>
To: elson at pico-systems.com, "General Discussion: On-Topic and
Off-Topic Posts" <cctalk at classiccmp.org>
Subject: Re: Could somebody please help me identify this board?
Message-ID:
<CAFrGgTTLic5hnQRwpDjAc-
syKRd13cpTtbU0ZC3d41dAFaw=hQ at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
On Tue, Dec 6, 2016 at 7:32 PM, Jon Elson <jonelson126 at gmail.com> wrote:
> It appears to be an extended-length Multibus II board with 2 8-bit DACs it. Output
for an XY scope?
Extended-length Multibus. Definitely not Multibus II, which uses Eurocard
6Ux220 form factor with two 96-pin DIN 41612 connectors.
------------------------------
Message: 11
Date: Wed, 7 Dec 2016 02:34:26 -0500
From: Evan Koblentz <cctalk at snarc.net>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Have lunch with Lee Felsenstein
Message-ID: <42f12b6a-d3ab-8739-2d83-0f7f420145eb at snarc.net>
Content-Type: text/plain; charset=utf-8; format=flowed
Only 12 hours left to bid on lunch with legendary computer engineer Lee
Felsenstein! This benefits Vintage Computer Federation, a 501(c)3
non-profit devoted to enabling collectors, growing the hobby, and
spreading awareness of computer history. Please see
https://www.charitybuzz.com/catalog_items/lunch-for-3-with-personal-
computing-social-media-icon-1198500.
------------------------------
Message: 12
Date: Wed, 7 Dec 2016 16:10:16 +0000
From: Tom Moss <tomjmoss at googlemail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Wanted: Terminator for an RL02
Message-ID:
<CAN69K+bG2C4xg5i7N_Vyc7gvGVYd7otHJwwqg2Rp4CytokhqfA at mail.
gmail.com>
Content-Type: text/plain; charset=UTF-8
Hi All,
Does anyone have a spare RL02 terminator for sale?
Regards,
-Tom
End of cctalk Digest, Vol 30, Issue 7
*************************************