Most PCs come with this port, traditionally used for connecting printers, and sometimes hobbyist kits like our Simple Parallel port LED Board “How to attach and program an LED to the parallel port on a PC”). Some newer ones have however done away with this with the rise of the USB printers.

It uses (as the name implies) a Parallel Data Stream.

Parallel Port Pins

Parallel Port Pins

Pin No Name Direction In/out Register Hardware Inverted
1 nStrobe In/Out Control Yes
2 Data 0 Out Data
3 Data 1 Out Data
4 Data 2 Out Data
5 Data 3 Out Data
6 Data 4 Out Data
7 Data 5 Out Data
8 Data 6 Out Data
9 Data 7 Out Data
10 nAck In Status
11 Busy In Status Yes
12 Paper-Out / Paper-End In Status
13 Select In Status
14 nAuto-Linefeed In/Out Control Yes
15 nError / nFault In Status
16 nInitialize In/Out Control
17 nSelect-Printer / nSelect-In In/Out Control Yes
18 - 25 Ground Gnd

In the table - when hardware inverted is yes, it means that when you write a 1 to this pin, it will output a 0, and vice versa.

In the past, this was used to connect many peripherals, like you would now use the IO pins of a Raspberry Pi or Arduino. You can learn to connect things to this, and program this port at our Simple Parallel port LED Board article.