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Centronics

General
One of the most used printer interfaces, since every Intel/DOS/Windows based Personal Computer today has a Sub-D25 female connector which is called LPT1.

Pinning 36 pin Amphenol

MaleFemale
 
PinSignalAbbr.Source
1Data Strobe (low)STROBEComputer
2Data Bit 1 (LSB)D1Computer
3Data Bit 2D2Computer
4Data Bit 3D3Computer
5Data Bit 4D4Computer
6Data Bit 5D5Computer
7Data Bit 6D6Computer
8Data Bit 7D7Computer
9Data Bit 8 (LSB)D8Computer
10Acknowledge (low)ACKPrinter
11Busy (high)BUSYPrinter
12Paper End (high)PEPrinter
13Select (high)SELPrinter
14Supply Ground -
15Oscillator Transmit Printer
16Logical Ground -
17Chassis Ground -
18+5 Vdc+VPrinter
19Return Data Strobe -
20Return Data Bit 1 -
21Return Data Bit 2 -
22Return Data Bit 3 -
23Return Data Bit 4 -
24Return Data Bit 5 -
25Return Data Bit 6 -
26Return Data Bit 7 -
27Return Data Bit 8 -
28Return ACK -
29Return BUSY -
30Return Input Prime-
31Input Prime (low) Computer
32Fault (low)FAULTPrinter
33---
34---
35---
36---

Pinning Sub-D25

MaleFemale
PinSignalAbbr.Source
1Data Strobe (low)STROBEComputer
2Data Bit 1 (LSB)D1Computer
3Data Bit 2D2Computer
4Data Bit 3D3Computer
5Data Bit 4D4Computer
6Data Bit 5D5Computer
7Data Bit 6D6Computer
8Data Bit 7D7Computer
9Data Bit 8 (LSB)D8Computer
10Acknowledge (low)ACKPrinter
11Busy (high)BUSYPrinter
12Paper End (high)PEPrinter
13Select (high)SELPrinter
14Auto Line Feed (low)LFComputer
15Error (low)ERRORPrinter
16Initialize Printer (prime-low)PRIMEComputer
17Select Input (low)SELComputer
18Return/groundGND-
19Return/groundGND-
20Return/groundGND-
21Return/groundGND-
22Return/groundGND-
23Return/groundGND-
24Return/groundGND-
25Return/groundGND-

Functional Description
STROBE:Active low pulse used to transfer data into the printer.Pulse with must be between 0.5 and 500 microseconds for most printers.
Dn:Data lines, high is a one. 
ACK:Active low pulse indicates that data has been received and the printer is ready to accept more. 
BUSY:A high signal indicates that the printer cannot receive data. 
PE:A high signal indicates that the printer is out of paper (Paper End) 
SELECT OUT:A high signal indicates that the printer is on-line 
AUTO FEED:A low signal indicates to the printer that a line feed is required after each Carriage return.This signal is used as a ground line by some manufacturers.
OSCXT:A 100-200 KHz signal used by true Centronics printers only. 
+5V:+5VdcNot provided by all manufacturers
PRIME:A low signal resets the printer to its power-up state and the printer buffer is cleared 
FAULT:A low signal indicates that the printer is in an off-line or error state 
LINE COUNT:Used by true Centronics printers only.Most of the time not used
SELECT IN:A high signal indicates to the printer that a DC1/ DC3 code is valid.This signal is used by a few manufacturers

Sub-D25 to Centronics cable
Sub-D25 Centronics 36
1---1
2---2
3---3
4---4
5---5
6---6
7---7
8---8
9---9
10---10
11---11
12---12
13---13
14---14
15---32
16---31
17---36
18---33
19---19
20---21
21---23
22---25
23---27
24---29
25---30


Resources: