Centronics Connectors
The 36-pin Centronics connector is commonly used for
parallel printer interfaces. The 50-pin connector is often used for external
SCSI interfaces.
Here's a look at the female 36-pin Centronics connector, as viewed from the
pin side (not the solder side). (The female connector is mounted on the
printer, the male connector is used for the printer cable.)
Here's a look at the male and female 50-pin Centronics connectors, as viewed
from the pin side (not the solder side). (The female connector is usually
mounted on the device, the male connector on the cable.)
Pin assignments for 36-pin Centronics printer connectors:
| Centronics Pin |
DB-25 Pin |
Name |
Direction |
Description |
| 1 |
1 |
STROBE |
PC-to-Printer |
Strobe |
| 2 |
2 |
D0 |
PC-to-Printer |
Data Bit 0 |
| 3 |
3 |
D1 |
PC-to-Printer |
Data Bit 1 |
| 4 |
4 |
D2 |
PC-to-Printer |
Data Bit 2 |
| 5 |
5 |
D3 |
PC-to-Printer |
Data Bit 3 |
| 6 |
6 |
D4 |
PC-to-Printer |
Data Bit 4 |
| 7 |
7 |
D5 |
PC-to-Printer |
Data Bit 5 |
| 8 |
8 |
D6 |
PC-to-Printer |
Data Bit 6 |
| 9 |
9 |
D7 |
PC-to-Printer |
Data Bit 7 |
| 10 |
10 |
/ACK |
Printer-to-PC |
Acknowledge |
| 11 |
11 |
BUSY |
Printer-to-PC |
Busy |
| 12 |
12 |
POUT |
Printer-to-PC |
Paper Out |
| 13 |
13 |
SEL |
Printer-to-PC |
Select |
| 14 |
14 |
/AUTOFEED |
PC-to-Printer |
Autofeed |
| 15 |
N/A |
n/c |
N/A |
Not used |
| 16 |
N/C |
0 V |
N/A |
Logic Ground |
| 17 |
N/C |
CHASSIS GND |
N/A |
Shield Ground |
| 18 |
N/C |
+5 V PULLUP |
Printer-to-PC |
+5 V DC (50 mA max) |
| 19-30 |
18-25 |
GND |
N/A |
Ground reference for signal pins 1-12, in most cables as twisted
pairs. |
| 31 |
16 |
/RESET |
PC-to-Printer |
Reset |
| 32 |
15 |
/FAULT |
Printer-to-PC |
Fault (Low when offline) |
| 33 |
N/C |
0 V |
N/A |
Signal Ground |
| 34 |
N/C |
N/C |
N/A |
Not used |
| 35 |
N/C |
+5 V |
Printer-to-PC |
+5 V DC |
| 36 |
17 |
/SLCT IN |
PC-to-Printer |
Select In (Taking low or high sets printer on line or off line
respectively) |
Click here to
see the pinout of DB-25 connectors.
50-Pin Centronics Connector Pin Assignments for
single-ended SCSI devices
| Pin |
Name |
Description |
| 1-11 |
GND |
Ground |
| 12-14 |
RES |
Reserved |
| 15-25 |
GND |
Ground |
| 26 |
DB0 |
Data Bus 0 |
| 27 |
DB1 |
Data Bus 1 |
| 28 |
DB2 |
Data Bus 2 |
| 29 |
DB3 |
Data Bus 3 |
| 30 |
DB4 |
Data Bus 4 |
| 31 |
DB5 |
Data Bus 5 |
| 32 |
DB6 |
Data Bus 6 |
| 33 |
DB7 |
Data Bus 7 |
| 34 |
PARITY |
Data Parity (odd parity) |
| 35 |
GND |
Ground |
| 36 |
GND |
Ground |
| 37 |
GND |
Ground |
| 38 |
TMPWR |
Termination Power |
| 39 |
GND |
Ground |
| 40 |
GND |
Ground |
| 41 |
/ATN |
Attention |
| 42 |
n/c |
Not connected |
| 43 |
/BSY |
Busy |
| 44 |
/ACK |
Acknowledge |
| 45 |
/RST |
Reset |
| 46 |
/MSG |
Message |
| 47 |
/SEL |
Select |
| 48 |
/C/D |
Control/Data |
| 49 |
/REQ |
Request |
| 50 |
/I/O |
Input/Output |
50-Pin Centronics Connector Pin Assignments for differential
SCSI devices
| Pin |
Name |
Description |
| 01 |
GND |
Ground |
| 02 |
+DB0 |
+Data Bus 0 |
| 03 |
+DB1 |
+Data Bus 1 |
| 04 |
+DB2 |
+Data Bus 2 |
| 05 |
+DB3 |
+Data Bus 3 |
| 06 |
+DB4 |
+Data Bus 4 |
| 07 |
+DB5 |
+Data Bus 5 |
| 08 |
+DB6 |
+Data Bus 6 |
| 09 |
+DB7 |
+Data Bus 7 |
| 10 |
+DBP |
+Data Bus Parity (odd Parity) |
| 11 |
DIFFSENS |
|
| 12 |
res |
Reserved |
| 13 |
TERMPWR |
Termination Power |
| 14 |
res |
Reserved |
| 15 |
+ATN |
+Attention |
| 16 |
GND |
Ground |
| 17 |
+BSY |
+Bus is busy |
| 18 |
+ACK |
+Acknowledge |
| 19 |
+RST |
+Reset |
| 20 |
+MSG |
+Message |
| 21 |
+SEL |
+Select |
| 22 |
+C/D |
+Control or Data |
| 23 |
+REQ |
+Request |
| 24 |
+I/O |
+In/Out |
| 25 |
GND |
Ground |
| 26 |
GND |
Ground |
| 27 |
-DB0 |
-Data Bus 0 |
| 28 |
-DB1 |
-Data Bus 1 |
| 29 |
-DB2 |
-Data Bus 2 |
| 30 |
-DB3 |
-Data Bus 3 |
| 31 |
-DB4 |
-Data Bus 4 |
| 32 |
-DB5 |
-Data Bus 5 |
| 33 |
-DB6 |
-Data Bus 6 |
| 34 |
-DB7 |
-Data Bus Pariy7 |
| 35 |
-DBP |
-Data Bus Pariy (odd Parity) |
| 36 |
GND |
Ground |
| 37 |
res |
Reserved |
| 38 |
TERMPWR |
Termination Power |
| 39 |
res |
Reserved |
| 40 |
-ATN |
-Attention |
| 41 |
GND |
Ground |
| 42 |
-BSY |
-Bus is busy |
| 43 |
-ACK |
-Acknowledge |
| 44 |
-RST |
-Reset |
| 45 |
-MSG |
-Message |
| 46 |
-SEL |
-Select |
| 47 |
-C/D |
-Control or Data |
| 48 |
-REQ |
-Request |
| 49 |
-I/O |
-In/Out |
| 50 |
GND |
Ground |
Click here to see the pin outs for
the DB-25 SCSI connector.
You can find additional SCSI info
here.
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