From the info I've received from the replies I know what the hardware requirements are. Appreciate the input guys. If anyone could help me on the software side where I want to display a 'box' on the screen with the value of the 'count' being displayed, with possibly an ability to scale the count to convert it to a linear movement, rather than a pulse count. Also I would be using the A & B signals from the encoder to discriminate direction of count. regards CL ::)