Connect a 240x128 LCD to a LPT-port: This tutorial explains how to connect a DataVision graphic LCD display to your LPT port by using a LPT-cable and some soldering skills.

Disclaimer: You will need some understanding of circuitry and wiring for this project. The writer of this article is not liable for any damage or injury resulting from improper use of this information. Images in the article were used with permission from the writer.

This tutorial explains how to connect a DataVision graphic LCD display to your LPT port by using a LPT-cable and some soldering skills.

In this example I will use a DataVision 240x128pixel Graphic LC-Display, but when you use a good connection-scheme, it will be possible to use this method to connect several brands of LCD displays like those made by Nan-Ya and Hyundia.

On the Dutch website , there is a where you can find a lot of links to where the datasheets of LCD displays are collected.

The DataVision 240x128pixel LCD

For the connection of the LPT-cable to the LC-Display you will need the following materials:

- A LCD display
- A LPT cable
- A soldering iron and solder wire
- Shrink tubing
- A hobby knive
- A pair of pliers
- Three resistors, 1/4watt 10 ohms, 12 ohms and 18 ohms
- Two potentio meters 1 kohm and 10 kohm
- One 100nF condensator
- One press button

The materials needed to make the connection

Preparing the LPT Cable

When you have collected all these materials, it is time to start the project.

A picture of the opened 25pins male connector which we will leave as it is

The choice of LPT cable is very important, in this example I’ve choosen for a 25-pins male cable (PC-side) to 36-pins Centronics (LPT-side). I’ve choosen this type of cable since the pin-housing is fairly easy to open, which enables you to see the colours and the pin numbers on the connector. This will make things a lot easier later on when I’ve to solder the wires to the LCD display.

On the other side of the LPT cable I opened the 36-pins Centronics connector in the same manner, and with a soldering iron I've loosened all the wires carefully from the connector.

Please note that all wires have to be removed from the connector.

Now I have a cable which has a 25-pin male LPT connector, and on the otherside 25 coloured wires.

The Wiring Diagram

Now is the cable ready to be connected to the LC-Display. But first we need a wiring diagram. Through the earlier mentioned ‘list with links to LCD information’ on I’ve found a (Dutch) website , where we will find some good designed wiring diagrams for several brands of LC-Displays.

On that website I found also this wiring diagram...

...and for the back light part:

The above drawn diagrams are made by Zotty, on the left hand side is the connection to the LPT-port and on the right hand side the connections to the LCD display.

The smaller diagram is for the controller of the back light.

The Soldering

First of all, I will melt some solder over the 20 pins of the LCD display, in order to prepare these pins for the soldering of the wires. When some solder is applied to the pins previous to soldering the wires, the latter ones will connect more easy.

Please note that you only have to apply a small amount of solder to the pins, too much is NOT good.

After the applying of the solder to the pins, it’s time to connect the wires. To prevent any possible short-circuit I’ve used about a ½" of shrink tubing around each wire. This shrink tubing has slide around the cable before you connect it.

When all the wires are connected according to the wiring diagram, I slide the shrink tubing around the connection points and with a hair dry blower (or paint stripper) I’ll shrink them firm on their spot.

The Back Light Control, Contrast Control, and the Reset Button

As you can see on the wiring diagram on the previous page, it is also possible to control the back light and the contrast, and there is a reset button.

These three controller units can be easily built on a small PCB, connected through some wires, in order to place this control unit somewhere else in your computercase.

I’ve made for this purpose a small PCB, using the two potentiometers, three resistors and the condensator and the reset button.

When you are ready with soldering, and every wire is connected,it will look like this:

Final Words

After all the hard labour, it is now time to connect the graphic LCD display to the LPT port of the computer.

Don't forget that the supply voltage of these kinds of LCD displays is only 5 (five!!) volts, so please connect them to the RED and the BLACK wire of your PC power supply molex.

Should it be connected to 12Volts (yellow & black from PSU), your screen will DIE instantly!!

The program , written by MaNDaRK and Mr.ChronoM, is a very good program, since it has been written especially for this kind of graphical LCD display.

When you decide to install PowerLCD, please take good note to the instructions of the programmers, since for Windows ’98 and higher Operation Systems you’ll need for example the extra program , in order to get direct hardware access to the LPT port.

But when all the required programs are installed, you really can enjoy the Graphic LCD display.

Ed. Note: If you have any other questions, feel free to checkout , or contact .