21 May
2020
21 May
'20
8:37 a.m.
https://www.vecmar.com/products/search.asp
Type in keyboard
The first result allows a terminal keyboard to be used on a PS/2 port.
The second result allows a PS/2 keyboard to be used on a terminal.
Not affiliated with seller, etc.
Cindy Croxton
Electronics Plus
1613 Water Street
Kerrville, TX 78028
830-370-3239 cell
sales at elecplus.com
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21 May
21 May
10:20 a.m.
On Thu, May 21, 2020 at 9:37 AM Electronics Plus via cctalk <
cctalk at classiccmp.org> wrote:
https://www.vecmar.com/products/search.asp
Type in keyboard
The first result allows a terminal keyboard to be used on a PS/2 port.
The second result allows a PS/2 keyboard to be used on a terminal.
From the limited information available (almost none),
it appears that they
are selling passive adapters that work with ADDS 4000 terminals
that use
PS/2 protocol on a modular jack.
As has been noted earlier in this thread, there are a huge number of
computers that use modular plugs and jacks for keyboard interfaces, and
there is NO standard for their electrical or protocol characteristics.
Plugging in the wrong combination can result in damage to either or both
devices. Even using the wrong modular cable can do that, because common
4P4C modular cables are wired with a flip (1 to 4, 2 to 3, etc), while
modular cables for computers are sometimes (e.g. Macintosh 128/512/Plus)
wired straight through (1 to 1, 2 to 2, etc.)
IMNSHO, there's a special place in hell reserved for those who have
designed equipment to (ab)use modular connectors other than for telephone
lines and 10BASEx Ethernet, and I really think a better connector should
have been chosen for 10BASEx.
DEC using MMJ may get a pass because they at least attempted to prevent
connecting the wrong stuff together.
6:42 p.m.
On Thu, May 21, 2020 at 10:20 AM Eric Smith via cctalk <
cctalk at classiccmp.org> wrote:
IMNSHO, there's a special place in hell reserved
for those who have
designed equipment to (ab)use modular connectors other than for telephone
lines and 10BASEx Ethernet, and I really think a better connector should
have been chosen for 10BASEx.
The whole concept of "if the plug fits, it will at least not blow up" is
kind of a late invention.
And I'm amazed when this actually holds true in situations where I wouldn't
quite expect that to be the case (e.g. all those electrically not quite
compatible PCI/PCI-X/PCIe variants that have coded notches to prevent you
from frying your computer/card. Except that you can
stick a PCI card
backwards into a PCIe slot)
DEC using MMJ may get a pass because they at least attempted to prevent
connecting the wrong stuff together.
Any ideas why it took so much longer for keyboard interfaces to converge
than most other peripherals? Display interfaces, HDDs/floppies/tapes etc.,
serial ports, and even mice converged on only a few variants more or less
the moment they became commonplace.
I'd really like some first hand insight into why anyone would want to
invent a new interface/protocol from scratch every time they
start developing a new machine (I'm mostly talking about the "simple async
serial protocol sending up/down events" kind). Luckily there are only 12
different ways to wire a 4P4C, but there exist way more incompatible
keyboards using that connector. Is it really easier to develop an
incompatible serial keyboard interface from scratch than to re-use one that
already exists?
[actually, I kinda know, because of course it's easier to do a one-off and
not care about documentation, licensing, extensibility, or
forwards/backwards compatibility]
22 May
22 May
5:26 a.m.
On Fri, 22 May 2020 at 05:26, Rico Pajarola via cctalk
<cctalk at classiccmp.org> wrote:
The
whole concept of "if the plug fits, it will at least not blow up" is
kind of a late invention.
Ha!
I have an old external 3.5" IDE disk enclosure. It's a good enclosure,
too -- Firewire 800 _and_ USB 2 _and_ eSATA. It has the internal drive
from my old iMac G5 in it. The iMac suffered from
failing capacitors
and I coaxed a little more life from it by making its HD
external.
I wish to retrieve its contents.
It has a very odd power connector. It's a DIN plug with quite a few
pins -- 7 or 8 and a plastic locator. Unique PSU.
As I have been on mandatory working-from-home for a couple of months,
I took my Mac mini setup in the bedroom apart and stashed the bits
away, and set up
my work laptop with 2 old external screens as a home office. One
ancient Eizo screen and a slightly more modern HDMI one.
Snag: I failed to pack the modern HDMI screen's PSU brick away with it.
This led to a lot of frantic hunting. I found the power brick, and some others.
The snag is this. I now have _two_ power bricks for the external
drive. Both deliver the requisite *both* 12V and 5V. Both have the
right DIN plug and fit.
But they're wired differently. One's ground pins are the other's 12V pins.
I think this is now resolved but it was an interesting question: one
brick will power the drive, while the other, with an identical
connector, is more or less guaranteed to release the magic smoke from
the external enclosure.
?
--
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Email: lproven at cix.co.uk ? gMail/gTalk/gHangouts: lproven at gmail.com
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9:21 a.m.
On Fri, 22 May 2020, Liam Proven via cctalk wrote:
Ha!
I have an old external 3.5" IDE disk enclosure. It's a good enclosure,
too -- Firewire 800 _and_ USB 2 _and_ eSATA. It has the internal drive
from my old iMac G5 in it. The iMac suffered from failing capacitors
and I coaxed a little more life from it by making its HD external.
I wish to retrieve its contents.
It has a very odd power connector. It's a DIN plug with quite a few
pins -- 7 or 8 and a plastic locator. Unique PSU.
As I have been on mandatory working-from-home for a couple of months,
I took my Mac mini setup in the bedroom apart and stashed the bits
away, and set up
my work laptop with 2 old external screens as a home office. One
ancient Eizo screen and a slightly more modern HDMI one.
Snag: I failed to pack the modern HDMI screen's PSU brick away with it.
This led to a lot of frantic hunting. I found the power brick, and some others.
The snag is this. I now have _two_ power bricks for the external
drive. Both deliver the requisite *both* 12V and 5V. Both have the
right DIN plug and fit.
But they're wired differently. One's ground pins are the other's 12V pins.
I think this is now resolved but it was an interesting question: one
brick will power the drive, while the other, with an identical
connector, is more or less guaranteed to release the magic smoke from
the external enclosure.
Similarly, I have a few 3.25" drives. NO, not 3.5"; not 3.0". 3.25"
was
the entry in the "shirt pocket disk" wars that Dysan bet the company on.
(remember their disks?) Another discussion.
OB_Tangent: Georgre Morrow said that the solution would be to cut a deal
with clothing manufacturers to make shirt pockets 5.25" or even 8"
3.0" drives (Amdek, Amstrad, etc.) use same connectors as "standard"
5.25", with "molex" power connector (I don't know what the CORRECT name
is
for that connector).
But, I have some 3.25" drives that use same connectors as "standard"
3.5"
drives, ("4 pin Berg"?) EXCEPT 5V and 12V are swapped in their positions
in the coneectors!
9:29 a.m.
But, I have some 3.25" drives that use same
connectors as "standard" 3.5"
drives, ("4 pin Berg"?) EXCEPT 5V and 12V are swapped in their positions
in the coneectors!
I have an Archive Sidewinder tape drive on one of my PERQs. The power
connector is the same as a 5.25" floppy drive power connector but the
2 voltages are +5V and +24V. At least the +5V pin is where you expect
it.
I am told some Sun workstations (Sun 2's???) had a power harness to
feed both 5.25" drives and a Sidewinder. The only dfference between
the connectors was the colours of the wires going to them.
Of course plugging an RS232 cable (DB25, none of this DE9 nonsense!)
into a PC printer port (or a PC printer cable into an RS232 port) is a
good way to let magic smoke out of some TTL chips...
It didn't let any magic smoke out, but I once had to sort out a
10base2 ethernet system that was behaving very oddly. Putting a 'scope
on the cable showed a signal the likes of which I'd never seen on
ethernet before. I cranked the timebase down and recognised it.
Composite video (RS170-like). Some 'genius' had plugged an unused
ethernet T-piece into the BNC connector on the back of a VT220...
-tony
10:21 a.m.
On Fri, 22 May 2020, Tony Duell wrote:
Of course plugging an RS232 cable (DB25, none of this
DE9 nonsense!)
into a PC printer port (or a PC printer cable into an RS232 port) is a
good way to let magic smoke out of some TTL chips...
IBM tried to use the [INADEQUATE] protection of opposite gender. Which
won't help if there is a sufficient pile of random other cables,
OR, college administrators purchasing "gender-changers" for adding a
second parallel printer! (on slot 8 of the 5160)
(For those not familiar, IIRC, slot 8 of the XT/5160 has differences in
buffering; to avoid accidental misuse, IBM provided the XT with a "free"
RS232 card to fill up that slot)
Later, when they got 286, 386, 486, and Pentium machines, they dug out
their gender-changers to see whether the parallel printer would work on
any male DB25 connectors on those machines. I wonder if THAT is why IBM
switched from DB25 to DE9 for serial port.
DE9 was used for 5150 CGA and MDA (not quite compatible)
AND for the early Microsoft "Bus mouse"
and, with opposite gender for "modern" RS232 ports.
DA15 was used for 5150 analog input (joystick) and
some people use it as a specialized video connection.
And, of course, the 5150 used 5 pin DIN for both keyboard AND cassette.
On the back, out of sight. ("MY left, or YOUR left?")
TRS80 [model 1] had used THREE 5 pin DINs on the back and side by side
for power, video and cassette.
"Sentience is the ability to learn from misteaks; wisdom is the ability to
learn from somebody else's previous misteaks."
Around here, IBM never had a cable available for cassette, but the Radio
Shack #26-1207 worked.
10:28 a.m.
On Fri, May 22, 2020 at 6:21 PM Fred Cisin via cctalk
<cctalk at classiccmp.org> wrote:
On Fri, 22 May 2020, Tony Duell wrote:
A lot of manufacturers, including major ones used the wrong gender of
connector on their RS232 ports... A socket wired as a DTE is common.
The HP150 is a classic... HP did just that (2 serial ports, wired as
DTEs, but sockets on the main unit). There was an option board which
included a parallel port. It used a DB25 _plug_. But it gets better,
The PCB was clearly designed for a DB25 socket, which would have had a
pinout compatible with the IBM parallel port. It appears that at the
last moment HP changed to a plug (I guess so you couldn't plug the
official HP cables into the wrong connectors). The result is that the
pins are mirrored compared to IBM, strobe is on pin 13, Data 0 on pin
12, etc...
-tony
Of course plugging an RS232 cable (DB25, none of
this DE9 nonsense!)
into a PC printer port (or a PC printer cable into an RS232 port) is a
good way to let magic smoke out of some TTL chips...
IBM tried to use the [INADEQUATE] protection of opposite gender. Which
won't help if there is a sufficient pile of random other cables,
9:35 a.m.
On Fri, 22 May 2020 at 18:21, Fred Cisin via cctalk
<cctalk at classiccmp.org> wrote:
Similarly, I have a few 3.25" drives. NO, not 3.5"; not 3.0". 3.25"
was
the entry in the "shirt pocket disk" wars that Dysan bet the company on.
(remember their disks?) Another discussion.
I remember the Zenith Minisport, a DOS laptop with 2" floppies:
http://oldcomputers.net/zenith-minisport.html
Don't think I ever saw one in real life, though.
Not sure any other computer ever used those media.
I own a number of Amstrad devices with 3" disks. But I don't think I
ever saw 3?"!
OB_Tangent: Georgre Morrow said that the solution
would be to cut a deal
with clothing manufacturers to make shirt pockets 5.25" or even 8"
Ha! :-)
It is a bit funny that people issued diktats, and designed products,
about and around pocket sizes.
Now I am doomed to ridiculously-thin phones with poor battery life.
This device was roundly mocked:
https://www.businessinsider.com/energizer-phone-with-huge-battery-failed-on…
It's about the same thickness as the original hard-disk-based iPods,
which sold in the tens of millions and were regarded as a pinnacle of
miniaturisation. I think our list member Mr Corlett was the first to
note that, that I saw.
3.0" drives (Amdek, Amstrad, etc.) use same
connectors as "standard"
5.25", with "molex" power connector (I don't know what the CORRECT
name is
for that connector).
With some adjustments, anyway, I believe...
https://www.cpcwiki.eu/index.php/DIY:Floppy_Drives
But, I have some 3.25" drives that use same
connectors as "standard" 3.5"
drives, ("4 pin Berg"?) EXCEPT 5V and 12V are swapped in their positions
in the coneectors!
:-o Nasty!
--
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Email: lproven at cix.co.uk ? gMail/gTalk/gHangouts: lproven at gmail.com
Twitter/Facebook/LinkedIn/Flickr: lproven ? Skype: liamproven
UK: +44 7939-087884 ? ?R (+ WhatsApp/Telegram/Signal): +420 702 829 053
12:35 p.m.
On 22/05/2020 17:21, Fred Cisin via cctalk wrote:
#> 3.0" drives (Amdek, Amstrad, etc.) use same connectors as "standard"
5.25", with "molex" power connector (I
don't know what the CORRECT name
is for that connector).
<pedant>
It's part of the AMP (now TE) Mate-N-LOK series.
But, I have some 3.25" drives that use same
connectors as "standard"
3.5" drives, ("4 pin Berg"?)? EXCEPT 5V and 12V are swapped in their
positions in the coneectors!
Not Berg, not even the same pitch. They're AMP Economy Interconnect
connectors, with a 2.50mm pitch.
</pedant>
--
Pete
Pete Turnbull
1:03 p.m.
3.0"
drives (Amdek, Amstrad, etc.) use same connectors as "standard"
5.25", with "molex" power connector (I don't know what the CORRECT
name is
for that connector).
<pedant>
It's part of the AMP (now TE) Mate-N-LOK series.
THANK YOU.
Seriously.
The pedantic nature of this list makes it a real treasure.
Simple GOOGLE and Wikipedia are buried in too many "definitive" wrong
answers. Such as calling 36 pin Blue ribbon "Centronics", "DB9", or
the
historic/antique uses of the yellow and black pair in phone wiring (NO, it
was NOT "always" for second line)
--
Grumpy Ol' Fred cisin at xenosoft.com
But, I have some 3.25" drives that use same
connectors as "standard" 3.5"
drives, ("4 pin Berg"?)? EXCEPT 5V and 12V are swapped in their positions
in the coneectors!
Not Berg, not even the same pitch. They're AMP Economy Interconnect
connectors, with a 2.50mm pitch.
</pedant>
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