Intermec EasyCoder 601 XP Service Manual page 114

16.3 Parallel
Communication Port
"centronics:", cont'd.
Modification:
Although IEEE 1284 specifies a SELECT
IN signal to be set low by the host during
communication, many hosts do not sup-
port this signal. Therefore, we have modi-
fied the Centronics interface board so
the SELECT IN signal is no longer re-
quired.
P1
INT3741
1
2
SELIN
3
INIT
Gnd
4
STROBE
5
CRSTR
6
BUSY
7
CWSTR
8
CROE
9
AF
10
PERR
11
SELECT
12
CWOE
13
ACK
14
ERROR
15
A2
16
A3
17
IOCS1E
18
IOWR
19
IORD
20
IOD0
21 IOD1
22 IOD2
23 IOD3
24 IOD4
25 IOD5
26 IOD6
27 IOD7
28 SYSCLK
29 RESET
30
31
C1 C2
C4
32
33
34
Intermec EasyCoder 601 XP – Service Manual Ed. 3
1-971603-28 Centronics pcb.; Components
1-971603-28 Centronics pcb.; Schematics
IC1
19
1Q
18
2Q
17
3Q
16
4Q
15
5Q
14
6Q
13
7Q
12
8Q
74HCT574
74HCT14 74HCT14
STROBE
4 3 2 1
IC3B IC3A
R1
VCC
C3
R2
VCC
R3
Gnd
1-971603-02-P01
L1-L17
L15
L16
L17
IC2
L14
L13
L12
L11
R3
L10
R2
L8
L7
L6
L5
IC1
L4
L3
L2
L1
L9
IC3
1
OC
11
CLK
2
‹ 1D
3
2D
4
3D
5
4D
6
5D
7
6D
8
7D
9
8D
IC2A
1
G
ACK 2 18
A1 ‹ Y1
BUSY 4 16
A2 Y2
PERR 6 14
A3 Y3
SELECT 8 12
A4 Y4
74AC244
IC2B
19
G
11 9
ERROR
A1 ‹ Y1
13 7
A2 Y2
15 5
A3 Y3
17 3
A4 Y4
74AC244
INIT
AF
Gnd
Chapter 16
P1
P1
C2
RN1
L1
L2
L3
L4
L5
L6
L7
L8
CGND
L9
L10
L11
L12
L13
L14
L15
L16
L17
Gnd
CGND
IC3C
5 6
74HCT04
IC3D
9 8
74HCT04
IC3E
11 10
74HCT04
IC3F
13 12
74HCT04
Gnd
Interfaces
P1
P2
1
DSTROBE
2
D0
3
D1
4
D2
5
D3
6
D4
7
D5
8
D6
9
D7
10
ACK
11
BUSY
12
PE
13
SELECT
14
AF
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
INIT
32
ERROR
33
34
35
36
113