G8MNY  > IBM      11.01.18 02:05l 35 Lines 1420 Bytes #999 (0) @ WW
BID : 5287_GB7CIP
Subj: IBM XT/AT Keyboard connections
Path: DB0NMS<DB0UHI<DB0OSN<DB0RES<IR2UBX<IZ3LSV<I0OJJ<GB7CIP
Sent: 180110/1042Z @:GB7CIP.#32.GBR.EURO #:5287 [Caterham Surrey GBR] $:5287_GB
From: G8MNY@GB7CIP.#32.GBR.EURO
To  : IBM@WW

5 Pin DIN Looking at Plug Pins      Function
or Computer socket cons.

           5 3 4                   1 CLOCK
          2     1                  2 DATA
                                   3 RESET (not)
             ^                     4 GND
                                   5 +VE (e.g. 12V feeding keyboard +5V Reg)

NB. AT & XT keyboard use quite different data code sets, so some early
keyboards had a switch to change over between these. The encoding is not only
different per key, but the AT one sends 1 code for key down & another code for
key release, whereas the XT ones just keep repeating the keydown code.
------------------------------------------------------------------------------
PS2 Modifications.
Fitting a normal DIN on a keyboard cable in place of the PS/2-type connection.
Which avoids the expense of an adapter.

Keyboard End                 PS/2 DIN connection        5-pin DIN
looking into the plug          Function
_ _ _ _ _ _    1 NC            1 Data                    1 Brn
1 2 3 4 5 6    2 White         2 No Connection           2 Wh
               3 Black         3 Ground                  3 NC
               4 Brown         4 5V DC                   4 Bk
               5 Red           5 Clock                   5 Red
               6 NC            6 No Connection


Why Don't U send an interesting bul?

73 De John, G8MNY @ GB7CIP


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