Below on this Draytek page, you will find links for downloading Vigor530 driver you need.
A Precision T3500 driver is an important program for your Draytek laptop or computer, as it promotes correct functioning of your Precision M6300 device. Moreover, a driver can promote correct functioning of any other device, e.g., a printer, a scanner or a display card. As a rule, your USB2RS232 PL2303 unit is already furnished with a CD with the proper Vigor530 driver set. If the CD is lost, please take advantage of the USB2RS232 PL2303 link for Vigor530 downloading.