PS/2-to-AT keyboard adapter

[Chris Giese]

Hi,

Do PC keyboards with "AT" connectors (the big 5-pin DIN plug)
use the same voltage levels and signalling as keyboards with
PS/2 connectors?

Will a PS/2 keyboard work if I cut off the PS/2 plug, solder
on an AT connector, and plug it into an old PC?

Otherwise, where do I get one of these? (Jameco P/N 189771):
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&productId=189771&catalogId=10001&freeText=189771&app.products.maxperpage=15&storeId=10001&search_type=jamecoall&ddkey=http:StoreCatalogDrillDownView

(Despite being listed as available, it is not.)

 

[Michael A. Terrell]

Chris Giese wrote:

Hi,

Do PC keyboards with "AT" connectors (the big 5-pin DIN plug)
use the same voltage levels and signalling as keyboards with
PS/2 connectors?

Will a PS/2 keyboard work if I cut off the PS/2 plug, solder
on an AT connector, and plug it into an old PC?

Otherwise, where do I get one of these? (Jameco P/N 189771):
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&productId=189771&catalogId=10001&freeText=189771&app.products.maxperpage=15&storeId=10001&search_type=jamecoall&ddkey=http:StoreCatalogDrillDownView

(Despite being listed as available, it is not.)

Those were shipped with a lot of keyboards and sold in computer
stores for years. Call a few computer shops or hit thrift stores.

Here is one on Ebay for 99 cents and free shipping:

<http://cgi.ebay.com/PS-2-Keyboard-Adapter-Mini-Din-6-F-Din-5-M-/380294544457?pt=LH_DefaultDomain_0&hash=item588b523c49>


--
For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!

 

[larry moe 'n curly]

Chris Giese wrote:

Hi,

Do PC keyboards with "AT" connectors (the big 5-pin DIN plug)
use the same voltage levels and signalling as keyboards with
PS/2 connectors?

Will a PS/2 keyboard work if I cut off the PS/2 plug, solder
on an AT connector, and plug it into an old PC?

Otherwise, where do I get one of these? (Jameco P/N 189771):
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&productId=189771&catalogId=10001&freeText=189771&app.products.maxperpage=15&storeId=10001&search_type=jamecoall&ddkey=http:StoreCatalogDrillDownView

(Despite being listed as available, it is not.)

The adapter in the picture is exactly the opposite of what you need.
It's for using a PS/2 keyboard with an old AT motherboard. You
instead
need something like this:

http://shop.ebay.com/?_from=R40&_trksid=p5197.m570.l1313&_nkw=ps2+at+keyboard+adapter&_sacat=See-All-Categories

There are also rigid 1-piece adapters at Ebay, but I prefer something
with a
short cable because it doesn't stick out so far in back, and a rigid
adapter
makes it easy to snap off the PS/2 socket on the motherboard.

I use an old IBM Model M keyboard with AT cable and have it plugged
into
an adapter cable that fits the PS/2 socket of my ATX motherboard.

 

[D Yuniskis]

Hi Chris,

Chris Giese wrote:

Do PC keyboards with "AT" connectors (the big 5-pin DIN plug)
use the same voltage levels and signalling as keyboards with
PS/2 connectors?

Yes -- more or less. I.e., given that you are connecting to
an "old PC", don't expect any of the "magic buttons" common on
newer keyboards to work. In fact, don't "expect" anything
from them (including expecting them to be IGNORED).

There are a couple of different keyboard interface protocols
that the keyboard controller will/should support. Depending on
how ancient your PC is, how the BIOS handles them may vary.

Be advised many *OLD* machines didn't tolerate the keyboard
being unplugged/plugged while powered on (older keyboards
consumed more power and this often lead to the keyboard
fuse -- in the PC -- blowing; doubtful a problem with a newer
keyboard).

Will a PS/2 keyboard work if I cut off the PS/2 plug, solder
on an AT connector, and plug it into an old PC?

Depends on what you call "old". E.g., I have still some Compaq
Portable III's here (286 lunchbox).

Otherwise, where do I get one of these? (Jameco P/N 189771):

(Despite being listed as available, it is not.)

Your local computer supply place will have them. Maybe even
rat shak.

 

[larry moe 'n curly]

Oops. You did choose the right adapter after all. I got it wrong
because all my good keyboards are the AT type with the big plug, so I
never assumed anybody would need an adapter for an AT motherboard.

 

[Chris Giese]

D Yuniskis <not.going.to.be@seen.com> wrote:

don't expect any of the "magic buttons" common on
newer keyboards to work.

Ah -- an added bonus

Depends on what you call "old". E.g., I have still some Compaq
Portable III's here (286 lunchbox).

The system in question is a Pentium 1 with 16 meg of RAM.

Your local computer supply place will have them. Maybe even
rat shak.

OK, I'll take a look.

Thanks everyone.