Parallel Port (Aux1); Parallel Port (Aux1) Diagram - Wyse WY-120 Maintenance Manual

Parallel Port (AUX1)
(U11 and U12)
Figure 4-6 Parallel Port (AUX1)
Diagram
Section 4 4-7
The parallel port consists of a 74LS36S hex tri-state buffer and a
7 4LS377 octal latch (Figure 4-6). Outgoing data is held in the
latch and incoming status is read through the buffer. The data to
and from the parallel port is multiplexed with the font data.
+SV
1
R9
S10
>
2
..1
STAB
....,
c
Q4
....,
t-
......,
R17
2N3904
Strobe
1
A2 8
P2
v
Printer
S10
Port
E
OB2S
7 LS377
3
10
11'"'
_2_
_a
06
4
20
20
s
_§_
04
7
30
3(1 6
4
=D2
8
40
40 9
2
00
13
so
sr.
12 3
01
14 60
~;1
1S
s
03
17
6-i
70
7,., 16 7
OS
18
80
&rl 19 9
07
1
a
"'I
.......!!..
>
U11
10
ACK
1S
ERRc5R
12
11
PE
17
BUSY
~
7LS36S
18
1A
1Y 3
4
2A 2Y S
19
6
3A 3Y
.L
20
~4A 4Y~
21
~SA SY~
22
23
14 6A 6Y 13
24
1
...i
G1
2S
1 ~
G2 U12