Parallel Port

The parallel port has been introduced to control a printer. Since printers are output devices there where 8 outputs to pass an ASCII character to the printer and some inputs to get the status back. The parallel port got quickly used for other things and got expanded, therefore the following version can appear. Some BIOS allow to choose between them

Type

Date of Introduction

Bidirectional

DMA

Speed

Standard parallel port (Standard Parallel Port SPP)

1981

No

No

150 Kbyte/sec

Parallel port PS/2 (bidirectional)

1987

If

No

150 Kbytes/sec

Enhanced Parallel Port (EPP)

1994

If

No

2 Mbytes/sec

Extended Capability Port (ECP)

1994

If

If

2 Mbytes/sec

To use the the parallel port to control some custom hardware as LCDproc make sure DMA is disabled.

The Pinout of the parallel Port:

Pin

Name

Dir

1

Data Strobe

out

2 to 9

Data 0 to 7

out /(and in)

10

Acknowledge

in

11

Busy

in

12

Paper Out

in

13

Select

in

14

Autofeed

out

15

Error

in

16

Reset

out

17

Selected

out

18 to 25

Ground

 

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