Serial supports all of the most common USB to Serial adapters available, with or without drivers installed on your computer. There are a few devices that still require drivers, however, including several Keyspan serial adapters (see Keyspan Device Notes ).
If you encounter a device that doesn't work with Serial, please let us know, and don't forget to include as much information about the device as possible, along with a debug log (see How do I enable logging? ) including the USB product and vendor ids. In many cases the driver for the device already exists and we just need to add the product information to our database of supported devices.