DRO on computer?

Unless I am mistaken (and I could very well be) I read something about
using a PC, some scales mounted to the ways of a machine and a serial
cable to connect them to the computer. The computer uses a software
package that works directly with the scales to operate just like a
dedicated DRO.

Am I dreaming here or does such a setup exist? Where does one find
the hardware and/or the software?

Any leads will be greatly appreciated.