USB-to-serial adapter

Currently, USB to TTL-level UART converters are used extensively by students and hobbyist as they can be directly interfaced to microcontrollers.

The primary application scenario is to enable USB-based computers to access and communicate with serial devices featuring D-sub (usually DE-9 or DB-25) connectors or screw terminals, where security of the data transmission is not generally an issue.

The isolated version has opto-couplers and/or surge suppressors to prevent static electricity or other high-voltage surges to enter the data lines thereby preventing data loss and damage to the adapter and connected serial device.

Some chip models have drivers installed by default, including FTDI, while drivers for other chip models must be manually installed (e.g. for Windows and MacOS, WCH (Jiangsu Qin Heng) CH340,[2] Silicon Labs 210x,[3] Prolific PL2303[4]).

However, the characteristics of the virtual COM-port are not exactly the same as a real internal COM port, mainly due to data latency; which means that if very sensitive and precise data transfer is required, the USB to serial adapter might be unreliable and not a desired solution.