Keyboard - IBM 3278 Series Maintenance Information

(M) 01 A/Al FS
(D) 01A/A1GS
01 Sl/Jl
r---
---1"
14
0
B12
2
B13
g>
-
3
B04
16
003
4
DOS
17
-
BOS
-
S
006
W
-
B07
6
007
19
B06
7
012
142
Bl1
8
009
21
-
B09
9
010
22
Bl0
-
10
011
23
-
B08
11
008
24
-
0
12
013
2S
0
13
' - - -
0
'-----
---
14
2
3
16
4
17
S
18
6
19
7
20
8
21
9
22
10
23
11
12
----
Keyboard Connector
02
B2
013 B13
Plug End View
Probe Points
Line Name Static.
Scan Bits 0-6
Down
Keyboard
Cable
Scan Bit 4
Scan Bit 6
Scan Bit 2
+S
KB Ack
Internal
Keyboard
Connecto
r--
B09
B13
013
003
002
KB Ident Bit 0
004
Clicker
B03
KB Ident Bit 1
005
Make/Break
B12
-S
KB Ident Bit 3
B06
010
8.SV
Scan Bit 1
Bll
POR
006
007
Data Avail
B07
KB Ident Bit 2
Scan Bit 3
009
Scan Bit 0
B08
DC Return
BOS
008
Scan Bit 5
Bl0
' - -
Active
Pulse up
2
Kybd 10 Bits 0-3 Down/Jmpr
Up nojmpr
3
Kybd ACK
Up Pulse down
4 Clicker
Down
Up click
S Make/Break Down
Up pulse
6
POR
Up Down after POR
7
Data Available Up Down pulse
Figure 4-16. Logic Gate to Keyboard Cables
4-18
SY27-2510-6