I have recently bought the USB serial cable from the SSDC website and tried to do a Firmware upgrade and I am confused. I installed the appropriate device drivers etc. and tried to do a firmware upgrade. It all started well and seemed to be working then the C7042 firmware program said it was not responding. I Switched everything off and unplugged the cables in the correct order. I then attached the LCD display to the C7402 PB and it is now blank. I have tried this several times now and I cannot get any further. Any suggestions please.