Features USB (Universal Serial Bus) to Straight-Through RS232 Serial Adapter Integrated 2500 Vrms Optical Isolation Circuits 500W Bi-Directional Surge Protection Circuits The ICUSB2321FIS 1-Port FTDI USB (Universal Serial Bus) to Serial RS232 Adapter Cable with Optical Isolation converts an available USB (Universal Serial Bus) 1.1 or 2.0 port into an RS232 DB9 port that can be used to connect, monitor & control your serial devices. The USB (Universal Serial Bus) to serial adapter features integrated optical isolation circuits & surge protection to protect your critical, sensitive control equipment against electrical damage, making it a viable solution for costly industrial serial devices.