17 Sep
2007
17 Sep
'07
7:29 p.m.
-------------Original Message:
Date: Sat, 15 Sep 2007 10:40:49 -0700
From: "Chuck Guzis" <cclist at sydex.com>
Subject: Re: PS/2 Interface (was: Wang 300 Calc]
On 15 Sep 2007 at 13:02, M H Stein wrote:
Funny how on the one hand I read the sentiment here
that people should be required
to pass a course in advanced computer science before being allowed to plug in a
computer, and then that they should be so simple to hook up that a retarded^H^H^H^H
mentally-challenged blind^H^H^H vision-impaired chimpanzee could do it;
just no pleasing some folks...
I dunno, Mike. I'm generally capable of operating most any computer,
but my eyesight is terrible (and not getting any better with age).
I'd sure as heck would like the assurance that whatever plug I'm
sticking into a receptacle at least isn't going to result in "magic
smoke" (see my earlier comment on wall wart perversion) even if I
didn't quite read the label on the box correctly.
------------Reply:
I know exactly what you mean about eyesight, so I probably wasn't very clear...
What I meant was that of all the things that *are* dumb like the PC printer
connector and Tony's AC plugs "criminally" used for other purposes, the
PS/2 mouse & keyboard ambiguity is as harmless as L & R audio connectors.
Mind you, IBM didn't "invent" that printer connector; lots of S-100 boxes
used
DB-25s for RS-232 *and* parallel printers and, what's even worse, they were usually
all female; almost makes sense, actually, since there were stock DB-25M<>CEN
cables around at the time whereas you usually wound up making your own serial
cables anyway. And wasn't a male connector a sort of "standard" for DTE
equipment?
Nevertheless, since Compaq could use the same port for a mouse or a keyboard,
I can't see either why when there are two separate ports they couldn''t be
interchangeable.
Some modern PCs even have interchangeable audio connectors; you can plug in
line in and out either way and it sorts out which is which.
And don't talk to me about wall-warts; what's really annoying is when the
equipment
doesn't state the voltage & polarity.
m
17 Sep
17 Sep
8:54 p.m.
On 17 Sep 2007 at 15:29, M H Stein wrote:
What I meant was that of all the things that *are*
dumb like the PC printer
connector and Tony's AC plugs "criminally" used for other purposes, the
PS/2 mouse & keyboard ambiguity is as harmless as L & R audio connectors.
Mind you, IBM didn't "invent" that printer connector; lots of S-100 boxes
used
DB-25s for RS-232 *and* parallel printers.
When I think about it, the MITS 8800 had connector punchouts for DB25
*only* in the back panel. DB25 seemed to be the lingua franca back
then for hobbyist interfaces. If one had an 8" floppy drive, one ran
the ribbon cable right through the crack between the back panel and
the case cover directly to the controller card(s). No DD50s.
Nevertheless, since Compaq could use the same port for
a mouse or a keyboard,
I can't see either why when there are two separate ports they couldn''t be
interchangeable.
Some modern PCs even have interchangeable audio connectors; you can plug in
line in and out either way and it sorts out which is which.
Indeed. I've owned a few of the "either spot is the right one"
systems.
Of course, now everyone's supposed to be using USB for all of that
stuff, right? ;)
Cheers,
Chuck
11:57 p.m.
When I think about it, the MITS 8800 had connector
punchouts for DB25
*only* in the back panel. DB25 seemed to be the lingua franca back
then for hobbyist interfaces. If one had an 8" floppy drive, one ran
the ribbon cable right through the crack between the back panel and
the case cover directly to the controller card(s). No DD50s.
I have an S100 amchine called a CASU Super C. It contains a Cromemco CPU
board, some other stnadard 64K RAM bvoard, a Micromation Doubler disk
controller and CASU-designed boot ROM and seiral interface boards.
The disk drive (a Persci) is in a separate box. The 50 wire interface
cable is split down the middle adn connected to a pair of DB25s...
-tony
18 Sep
18 Sep
12:50 a.m.
On Monday 17 September 2007 18:57, Tony Duell wrote:
I have a Cromemco "System 3" (?). It also has a Persci drive in it, a dual.
Is that what yours is?
There's apparently some sort of a problem with mine, as the floppy which was
in it when I got it had been tried so much and for so long that the initial
tracks were completely worn away, and you could see through it.
On perusing the service data for it, I notice that the drive uses a bunch of
_incandescent_ light bulbs for things like index sensor, etc. I would
imagine that one or more of these is likely to be the problem.
I'd deferred working on it because you can't do much with it in the computer
case, and I needed to make some sort of extension for the power cable to the
drive, which was a rather odd connector...
Nice machine, in that the S-100 card cage pulls out like a drawer. Too bad
it's not working.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
When I think
about it, the MITS 8800 had connector punchouts for DB25
*only* in the back panel. DB25 seemed to be the lingua franca back
then for hobbyist interfaces. If one had an 8" floppy drive, one ran
the ribbon cable right through the crack between the back panel and
the case cover directly to the controller card(s). No DD50s.
I have an S100 amchine called a CASU Super C. It contains a Cromemco CPU
board, some other stnadard 64K RAM bvoard, a Micromation Doubler disk
controller and CASU-designed boot ROM and seiral interface boards.
The disk drive (a Persci) is in a separate box. The 50 wire interface
cable is split down the middle adn connected to a pair of DB25s...
7:49 p.m.
On Monday 17 September 2007 18:57, Tony Duell wrote:
U
My machine is clearly not a Cromemco anything. The cases (separate box
for the drives), PSUs, backplane and some of the boards are made by CASU
in the UK
But yes, my Persci drive is a dual-disk unit. 4 heads on a voice coil
positioner. And motors to eject the disks.
When I
think about it, the MITS 8800 had connector punchouts for DB25
*only* in the back panel. DB25 seemed to be the lingua franca back
then for hobbyist interfaces. If one had an 8" floppy drive, one ran
the ribbon cable right through the crack between the back panel and
the case cover directly to the controller card(s). No DD50s.
I have an S100 amchine called a CASU Super C. It contains a Cromemco CP= board, some other stnadard 64K RAM bvoard, a
Micromation Doubler disk
controller and CASU-designed boot ROM and seiral interface boards.
The disk drive (a Persci) is in a separate box. The 50 wire interface
cable is split down the middle adn connected to a pair of DB25s...
I have a Cromemco "System 3" (?). It also has a Persci drive in it, a d=
ual. =20
Is that what yours is? There's apparently some sort of a problem with
mine, as the floppy which=
was=20
in it when I got it had been tried so much and for so long that the initi=
al=20
tracks were completely worn away, and you could see through it.
On perusing the service data for it, I notice that the drive uses a bunc=
h of=20
_incandescent_ light bulbs for things like index sensor, etc. I would=20
imagine that one or more of these is likely to be the problem.
Possibly. Typically with a problem like this I hook up the drive
exerciser and see just what the drive is, and isn't, doing.
-tony
17 Sep
17 Sep
11:54 p.m.
Mind you, IBM didn't "invent" that
printer connector; lots of S-100 boxes used
DB-25s for RS-232 *and* parallel printers and, what's even worse, they were usually
How about the Facit 4070 paper tape punch? It has a DB25 connector on the
rear panel. Inside there are 2 slots. One takes the control logic/driver
PCB for the punch. The parallel input of that is wired to one side of the
other eddge connecotr ; the other side of that connecotr is wired to the
DB25.
Most of the time theres a 'jumoper board' in that second slot, bringing
the parallel interface (TTL levels, close to Centronics but not quite)
on the DB25 connector.
But you could also get a serial interface PCB, really a a serial-parallel
converter. This pluggeed in place of the jumper board and gave an RS232
interface (normal pinouts, but with a current loop on a couple of the
normally spare pins) on said DB25.
So with that unit the only way to tell whether that DB25 is an RS232
serial interfxce or a TTL level parallel interface is to look at what PCB
is fitted.
-tony
18 Sep
18 Sep
2:07 a.m.
On 17/09/2007, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
So with that unit the only way to tell whether that
DB25 is an RS232
serial interfxce or a TTL level parallel interface is to look at what PCB
is fitted.
J*s*s wept!
To quote Douglas Adams:
ARTHUR: Don't ask me how it works or I'll start to whimper.
-- The Hitch-Hikers Guide to the Galaxy, Episode 11
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7:54 p.m.
On 17/09/2007, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Plkease remember that the Facit 4070 paper tape punch was bought by
people who tended to Read Th Fine Manual before plugging things in. And
would be tempted to check what PCBs were installed.
I still want to Read The Fine Manual, but I can't remember the last time
anything I bouight came witha Fine Manual. Certianly not anything in the
last 15 years.
-tony
So with that unit the only way to tell whether
that DB25 is an RS232
serial interfxce or a TTL level parallel interface is to look at what P=
CB
is fitted.
J*s*s wept! 
11:23 p.m.
New subject: PS/2 Interface
Tony Duell wrote:
I still want to Read The Fine Manual, but I can't
remember the last time
anything I bouight came witha Fine Manual. Certianly not anything in the
last 15 years.
You mean the one sheet of rice paper with instructions
in Chinese1,Chinese2,and Generic English.
-tony
19 Sep
19 Sep
11:32 p.m.
New subject: PS/2 Interface
Tony Duell wrote:
A scehamtic diagram looks much the same in any language, so the choice of
languages is not the main problem with modern manuals...
-tony
I still want to Read The Fine Manual, but I
can't remember the last time
anything I bouight came witha Fine Manual. Certianly not anything in the
last 15 years.
You mean the one sheet of rice paper with instructions
in Chinese1,Chinese2,and Generic English. 
20 Sep
20 Sep
5:23 a.m.
New subject: PS/2 Interface
From: ard at p850ug1.demon.co.uk> > > >
Tony Duell wrote:> > > > > I still want to Read The Fine Manual, but I
can't remember the last time > > > anything I bouight came witha Fine Manual.
Certianly not anything in the > > > last 15 years.> > > > You mean
the one sheet of rice paper with instructions> > in Chinese1,Chinese2,and Generic
English.> > A scehamtic diagram looks much the same in any language, so the choice
of > languages is not the main problem with modern manuals...> > -tony
Hi
Sure, what would 4r9 or 1k5 mean to someone in the US.
Even schematic symbols can be entirely different. About the
only thing I've seen that doen't seem to change is the wire.
Dwight
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