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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.)

Female 36-pin Centronics Connector

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.)

Male 50-pin Centronics Connector

Female 50-pin Centronics Connector

 

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 pinouts for the DB-25 SCSI connector.

You can find additional SCSI info here.


 

 

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This site last updated 7/11/2008