[Yaesu] computer control of FTdx1200

[Dick NY1E]

  I used to have control via a serial cable to my old computer, I got a new one without the serial port, so bought a USB to serial adapter cable (Prolific PL2303). The computer recognizes the com port but times out saying there's no radio. I can't find anything in the FT1200 menu that I need to turn on.... (I've been using the radio without computer for 6 months). Any ideas???de Dick NY1E