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SCSI External DB25 Female

Pin Name Direction Description
1 /REQ OUT Request
2 /MSG OUT Message
3 I/O OUT Input/Output
4 /RST IN/OUT Reset
5 /ACK IN Acknowledge
6 BSY IN/OUT Busy
7 GND ------ Ground
8 DB0 IN/OUT Data Bus 0
9 GND ------ Ground
10 DB3 IN/OUT Data Bus 3
11 DB5 IN/OUT Data Bus 5
12 DB6 IN/OUT Data Bus 6
13 DB7 IN/OUT Data Bus 7
14 GND ------ Ground
15 C/D OUT Control/Data
16 GND ------ Ground
17 /ATN IN Attention
18 GND ------ Ground
19 /SEL IN/OUT Select
20 PARITY IN/OUT Data Parity
21 DB1 IN/OUT Data Bus 1
22 DB2 IN/OUT Data Bus 2
23 DB4 IN/OUT Data Bus 4
24 GND ------ Ground
25 TMPWR IN/OUT Termination Power

SCSI DB25 to High Density DB50 Adapter

Description DB25 High Density DB50
Request 1 49
Message 2 46
Input/Output 3 50
Reset 4 45
Acknowledge 5 44
Busy 6 43
Data Bus 0 8 26
Data Bus 3 10 29
Data Bus 5 11 31
Data Bus 6 12 32
Data Bus 7 13 33
Control/Data 15 48
Attention 17 41
Select 19 47
Data Parity 20 34
Data Bus 1 21 27
Data Bus 2 22 28
Data Bus 4 23 30
Termination Power 25 38
All the unused pins at the DB25 end should be connected to pins 1-25 at the High-Density DB50

SCSI 50 Pin M Internal Normal

Pin Name Direction Description
2 DB0 IN/OUT Data Bus 0
4 DB1 IN/OUT Data Bus 1
6 DB2 IN/OUT Data Bus 2
8 DB3 IN/OUT Data Bus 3
10 DB4 IN/OUT Data Bus 4
12 DB5 IN/OUT Data Bus 5
14 DB6 IN/OUT Data Bus 6
16 DB7 IN/OUT Data Bus 7
18 PARITY IN/OUT Data Parity (odd Parity)
20 GND ------ Ground
22 GND ------ Ground
24 GND ------ Ground
26 TMPWR IN/OUT Termination Power
28 GND ------ Ground
30 GND ------ Ground
32 /ATN IN Attention
34 GND ------ Ground
36 /BSY IN/OUT Busy
38 /ACK IN Acknowledge
40 /RST IN/OUT Reset
42 /MSG OUT Message
44 /SEL IN/OUT Select
46 /C/D OUT Control/Data
48 /REQ OUT Request
50 /I/O OUT Input/Output

SCSI 68 Pin Normal

Pin Name Direction Description
1 GND ------ Ground
2 GND ------ Ground
3 GND ------ Ground
4 GND ------ Ground
5 GND ------ Ground
6 GND ------ Ground
7 GND ------ Ground
8 GND ------ Ground
9 GND ------ Ground
10 GND ------ Ground
11 GND ------ Ground
12 GND ------ Ground
13 GND ------ Ground
14 GND ------ Ground
15 GND ------ Ground
16 GND ------ Ground
17 TERMPWR IN/OUT Termination Power
18 TERMPWR IN/OUT Termination Power
19 RES ------ Reserved
20 GND ------ Ground
21 GND ------ Ground
22 GND ------ Ground
23 GND ------ Ground
24 GND ------ Ground
25 GND ------ Ground
26 GND ------ Ground
27 GND ------ Ground
28 GND ------ Ground
29 GND ------ Ground
30 GND ------ Ground
31 GND ------ Ground
32 GND ------ Ground
33 GND ------ Ground
34 GND ------ Ground
35 -DB12 IN/OUT -Data Bus 12
36 -DB13 IN/OUT -Data Bus 13
37 -DB14 IN/OUT -Data Bus 14
38 -DB15 IN/OUT -Data Bus 15
39 -DPB1 IN/OUT -Data Bus Parity (odd Parity)
40 -DB0 IN/OUT -Data Bus 0
41 -DB1 IN/OUT -Data Bus 1
42 -DB2 IN/OUT -Data Bus 2
43 -DB3 IN/OUT -Data Bus 3
44 -DB4 IN/OUT -Data Bus 4
45 -DB5 IN/OUT -Data Bus 5
46 -DB6 IN/OUT -Data Bus 6
47 -DB7 IN/OUT -Data Bus 7
48 -DPB IN/OUT -Data Bus Parity (odd Parity)
49 GND ------ Ground
50 GND ------ Ground
51 TERMPWR IN/OUT Termination Power
52 TERMPWR IN/OUT Termination Power
53 RES ------ Reserved
54 GND ------ Ground
55 -ATN IN -Attention
56 GND ------ Ground
57 -BSY IN/OUT -Bus is busy
58 -ACK IN -Acknowledge
59 -RST IN/OUT -Reset
60 -MSG OUT -Message
61 -SEL IN/OUT -Select
62 -C/D OUT -Control or Data
63 -REQ OUT -Request
64 -I/O OUT -In/Out
65 -DB8 IN/OUT -Data Bus 8
66 -DB9 IN/OUT -Data Bus 9
67 -DB10 IN/OUT -Data Bus 10
68 -DB11 IN/OUT -Data Bus 11

SCSI 68 Pin Differential

Pin Name Dir Description
1 +DB12 IN/OUT +Data Bus 12
2 +DB13 IN/OUT +Data Bus 13
3 +DB14 IN/OUT +Data Bus 14
4 +DB15 IN/OUT +Data Bus 15
5 +DPB1 IN/OUT +Data Bus Parity (odd Parity)
6 GND ------ Ground
7 +DB0 IN/OUT +Data Bus 0
8 +DB1 IN/OUT +Data Bus 1
9 +DB2 IN/OUT +Data Bus 2
10 +DB3 IN/OUT +Data Bus 3
11 +DB4 IN/OUT +Data Bus 4
12 +DB5 IN/OUT +Data Bus 5
13 +DB6 IN/OUT +Data Bus 6
14 +DB7 IN/OUT +Data Bus 7
15 +DPB IN/OUT +Data Bus Parity (odd Parity)
16 DIFFSENSE ? ?
17 TERMPWR IN/OUT Termination Power
18 TERMPWR IN/OUT Termination Power
19 RES ------ Reserved
20 +ATN IN +Attention
21 GND ------ Ground
22 +BSY IN/OUT +Bus is busy
23 +ACK IN +Acknowledge
24 +RST IN/OUT +Reset
25 +MSG OUT +Message
26 +SEL IN/OUT +Select
27 +C/D OUT +Control or Data
28 +REQ OUT +Request
29 +I/O OUT +In/Out
30 GND ------ Ground
31 +DB8 IN/OUT +Data Bus 8
32 +DB9 IN/OUT +Data Bus 9
33 +DB10 IN/OUT +Data Bus 10
34 +DB11 IN/OUT +Data Bus 11
35 -DB12 IN/OUT -Data Bus 12
36 -DB13 IN/OUT -Data Bus 13
37 -DB14 IN/OUT -Data Bus 14
38 -DB15 IN/OUT -Data Bus 15
39 -DPB1 IN/OUT -Data Bus Parity (odd Parity)
40 GND ------ Ground
41 -DB0 IN/OUT -Data Bus 0
42 -DB1 IN/OUT -Data Bus 1
43 -DB2 IN/OUT -Data Bus 2
44 -DB3 IN/OUT -Data Bus 3
45 -DB4 IN/OUT -Data Bus 4
46 -DB5 IN/OUT -Data Bus 5
47 -DB6 IN/OUT -Data Bus 6
48 -DB7 IN/OUT -Data Bus 7
49 -DPB IN/OUT -Data Bus Parity (odd Parity)
50 GND ------ Ground
51 TERMPWR IN/OUT Termination Power
52 TERMPWR IN/OUT Termination Power
53 RES ------ Reserved
54 -ATN IN -Attention
55 GND ------ Ground
56 -BSY IN/OUT -Bus is busy
57 -ACK IN -Acknowledge
58 -RST IN/OUT -Reset
59 -MSG OUT -Message
60 -SEL IN/OUT -Select
61 -C/D OUT -Control or Data
62 -REQ OUT -Request
63 -I/O OUT -In/Out
64 GND ------ Ground
65 -DB8 IN/OUT -Data Bus 8
66 -DB9 IN/OUT -Data Bus 9
67 -DB10 IN/OUT -Data Bus 10
68 -DB11 IN/OUT -Data Bus 11