Guidelines are provided for manufacturers wishing to migrate their present RS232 interface-based instruments to a USB interface. For instance, they can stay with RS232 and tell customers that want their PCs to have an RS232 port (but which only have a USB port) to obtain a RS232-to-USB converter. If the decision is made to switch to USB, decisions also have to be made regarding the hardware and software driver to be used for the device. Many companies provide USB chipsets, but resolving the driver software issue is also required. A custom device driver can be written, with a custom application program for communicating with the device, or the manufacturer can provide software development tools that allow other programmers to communicate with the device driver. This limits the device to operation only with manufacturer-provided devices or requires that customers write their own software for communication with the device. A very savvy solution is to develop the device so that when it is plugged into the USB port, it looks to the PC to be a standard RS232 port. The advantage of this approach is that it allows all existing serial communications software to communicate with the device just as it did before the change was made from RS232 to USB. Another choice is to design the USB interface to identify itself to a PC as a keyboard device, which makes Windows load its included USB keyboard device driver. This approach eliminates the need for driver development.