1.  Download the U90 software from this site. 2.  If you don't have a communication cable, find your local Unitronics distributor and get an MJ10-22-CS25.  Or order it online. 3.  If your computer doesn't have a serial port, you'll need a USB to serial converter.  Find one with the Prolific PL2303 chipset or get a Unitronics MJ10-22-CS35. Joe T.