2 Feb
2025
2 Feb
'25
4:42 p.m.
Message: 31
Date: Sun, 2 Feb 2025 07:29:15 +0000
From: Tony Duell <ard.p850ug1(a)gmail.com>
Subject: [cctalk] Re: RS232 then and now
On Sat, Feb 1, 2025 at 10:54 PM Fred Cisin via cctalk
<cctalk(a)classiccmp.org> wrote:
My vote for the worst connector screw-up is the AT&T (Olivetti) 6300. Its monochrome
monitor used a DB25 to supply both the signals and 12 volts to power the monitor.
Bob
IBM used a DB25 socket for their printer port at the computer end,
(male on the card for serial, female on the card for parallel "Centronics")
THAT, of course caused some idiots to attempt to use the parallel port for
serial and vice versa. "I just need a 'gender changer'!" :-)
The worst screw-up there (IMHO) came from HP in the HP150 series. This
machine had 2 RS232 serial ports as standard on DB25 sockets, wired
for some inexplicable reason as DTEs. There was an add-on board that
included a parallel printer port. To avoid confusion, this was a DB25
plug. But the board had been laid out for a DB25 socket using the IBM
PC pinout. The result was that stb/ ended up on pin 13, D0 on pin 12,
and so on.
-tony
2 Feb
2 Feb
8:31 p.m.
New subject: RS232 then and now
Didn't the original TRS-80 have a kind of screw up, where the tape and
display connector were the same?
Actually, years later the Atari Lynx had a similar mishap - the power
charger and headphone jack port look identical? (something like that, and
would cause damage if used incorrectly)
Steve
On Sun, Feb 2, 2025 at 6:53 PM Robert Feldman via cctalk <
cctalk(a)classiccmp.org> wrote:
My vote for the worst connector screw-up is the AT&T (Olivetti) 6300. Its
monochrome monitor used a DB25 to supply both the signals and 12 volts to
power the monitor.
Bob
Message: 31
Date: Sun, 2 Feb 2025 07:29:15 +0000
From: Tony Duell <ard.p850ug1(a)gmail.com>
Subject: [cctalk] Re: RS232 then and now
On Sat, Feb 1, 2025 at 10:54 PM Fred Cisin via cctalk
<cctalk(a)classiccmp.org> wrote:
>
> IBM used a DB25 socket for their printer port at the computer end,
> (male on the card for serial, female on the card for parallel
"Centronics")
> THAT, of course caused some idiots to attempt
to use the parallel port
for
serial
and vice versa. "I just need a 'gender changer'!" :-)
The worst screw-up there (IMHO) came from HP in the HP150 series. This
machine had 2 RS232 serial ports as standard on DB25 sockets, wired
for some inexplicable reason as DTEs. There was an add-on board that
included a parallel printer port. To avoid confusion, this was a DB25
plug. But the board had been laid out for a DB25 socket using the IBM
PC pinout. The result was that stb/ ended up on pin 13, D0 on pin 12,
and so on.
-tony
10:56 p.m.
New subject: RS232 then and now
On Sun, 2 Feb 2025, Steve Lewis via cctalk wrote:
Didn't the original TRS-80 have a kind of screw
up, where the tape and
display connector were the same?
Actually, years later the Atari Lynx had a similar mishap - the power
charger and headphone jack port look identical? (something like that, and
would cause damage if used incorrectly)
Steve
On the back (starboard side), there are THREE 5 pin DIN connectors. Power
(external cord-wart), video (composite), and cassette.
yes there were incidents regarding those.
The original IBM 5150 (PC) had two 5 pin DIN connectors on the back. For
keybpoard, and cassette IBM didn't sell a cable, but the Radio Shack
cassette cable for TRS80 worked fine..
3 Feb
3 Feb
12:02 a.m.
New subject: RS232 then and now
Ah, I wrote all about the IBM PC 5150 tape deck capability here:
5150: Setting up Tape Deck Connection (because the 5150 can) — voidstar
<https://voidstar.blog/5150-setting-up-tape-deck-connection-because-the-5150-can/>
Indeed it is exactly the same as the Tandy cable. I always assumed since
Microsoft had already ported BASIC to the earlier NEC PC-8001 and Tandy
Color Computer 1, the same developers ended up being involved in the IBM PC
project (and thus seeing the speed and urgency of that project, they just
suggest using that same connector and cable-- which in turn made it easier
for Microsoft to test and integrate their tape support on that systems
BASIC), so a schedule-win for both sides..
As a nit, it was always irritating that IBM (and similar) put that keyboard
jack all the way in the back side of the system. The Tandy 1000 finally
put that in the front - I never really looked into what board-layout
compromise they had to do to make that happen.
-Steve
On Mon, Feb 3, 2025 at 12:56 AM Fred Cisin via cctalk <cctalk(a)classiccmp.org>
wrote:
On Sun, 2 Feb 2025, Steve Lewis via cctalk wrote:
Didn't the original TRS-80 have a kind of
screw up, where the tape and
display connector were the same?
Actually, years later the Atari Lynx had a similar mishap - the power
charger and headphone jack port look identical? (something like that,
and
would cause damage if used incorrectly)
Steve
On the back (starboard side), there are THREE 5 pin DIN connectors. Power
(external cord-wart), video (composite), and cassette.
yes there were incidents regarding those.
The original IBM 5150 (PC) had two 5 pin DIN connectors on the back. For
keybpoard, and cassette IBM didn't sell a cable, but the Radio Shack
cassette cable for TRS80 worked fine..
10:09 a.m.
New subject: RS232 then and now
On Feb 2, 2025, at 7:42 PM, Robert Feldman via cctalk
<cctalk(a)classiccmp.org> wrote:
My vote for the worst connector screw-up is the AT&T (Olivetti) 6300. Its monochrome
monitor used a DB25 to supply both the signals and 12 volts to power the monitor.
Bob
DEC did something similar with the Pro, except they used a DA-15 connector to carry video
(monochrome as well as RGB), keyboard data (4800 bps UART) and 12 volt power.
paul
11:02 a.m.
New subject: RS232 then and now
On Mon, Feb 3, 2025 at 11:09 AM Paul Koning via cctalk <
cctalk(a)classiccmp.org> wrote:
DEC Rainbow too... And it's easy to short power to another line and take
out the line drivers in the keyboard...
Warner
On Feb 2, 2025, at 7:42 PM, Robert Feldman via
cctalk <
cctalk(a)classiccmp.org> wrote:
My vote for the worst connector screw-up is the AT&T (Olivetti) 6300.
Its monochrome monitor used a DB25 to supply both the signals and 12 volts
to power the monitor.
Bob
DEC did something similar with the Pro, except they used a DA-15 connector
to carry video (monochrome as well as RGB), keyboard data (4800 bps UART)
and 12 volt power.
6:06 p.m.
New subject: RS232 then and now
DEC did
something similar with the Pro, except they used a DA-15 connector
to carry video (monochrome as well as RGB), keyboard data (4800 bps UART)
and 12 volt power.
DEC Rainbow too... And it's easy to short power to another line and take
out the line drivers in the keyboard...
6:57 p.m.
New subject: RS232 then and now
On Mon, Feb 3, 2025, 7:06 PM Cameron Kaiser via cctalk <
cctalk(a)classiccmp.org> wrote:
Pretty sure the Pro as well (at least, I don't need to run any power to
the VR201).
Yes. And VT240 too.
Warner
--
> DEC did something similar with the Pro,
except they used a DA-15
connector
> to carry video (monochrome as well as RGB),
keyboard data (4800 bps
UART)
and 12
volt power.
DEC Rainbow too... And it's easy to short power to another line and take
out the line drivers in the keyboard...
------------------------------------ personal:
http://www.cameronkaiser.com/ --
Cameron Kaiser * Floodgap Systems * www.floodgap.com *
ckaiser(a)floodgap.com
-- Watch your mouth, kid, or you'll find yourself floating home. -- Han
Solo --
4
days inactive
5
days old
7 comments
6 participants
participants (6)
-
Cameron Kaiser -
Fred Cisin -
Paul Koning -
Robert Feldman -
Steve Lewis -
Warner Losh