The translator will continually sample the X and Y analog voltages from an oscilloscope's pen plotter output port, digitize them, and package the values into a series of plain text HP-GL plotter commands, which are output via a USB port to a file on a PC. The HP-GL file can be processed into a display image by any commonly available plotter emulator application, such as PrintCapture (http://www.printcapture.com).
Read all about it in my GitHub repository: 'Documentation/Translator Description.docx'. (See below)
See the demo video on YouTube: https://youtu.be/DhNy6BU84X4
Purchase a complete circuit board kit (Arduino UNO not included) from Aisler at http://aisler.net/p/MXSDNBWT.