I am using ProScan with various scanners for programming and control and for recording new talkgroups, etc. It works well with all the scanners except my 436 and 536. When I connect the programming cable to the scanner and press the decimal/no button for serial connect mode the computer gives me a "baw baw bomp" denial tone. I am running windows 7 on a laptop. I went to windows device manager and it says all usb ports are working properly an that the drivers are up to date. I have usb to serial drivers installed for other older scanners and they work fine with the same laptop. Any ideas of what I can try?