Buy RS232 USB to RS232C Serial Port Adapter - CNC Specialty Store
Amazon.com: Cable Matters USB to Serial Adapter Cable (USB to RS232, USB to DB9) 3 Feet : Electronics
USB to RS232 TTL | CMOS Adapter Cable with Terminal Block - Coolgear
USB to RS232 Converter Cable 1.0 meter - UMC-201
USB to RS232 DB9 Serial Adapter Cable - Serial Cards & Adapters | StarTech.com
USB to RS232 Converter - 6ft - CAB-11304 - SparkFun Electronics
4 Port Professional RS-232 USB 2.0 to Serial Adapter
Mettler Toledo RS232 to USB Converter Cable for XPR Microbalances and Ultra-Microbalances | Fisher Scientific
USB/Serial Converter [FT232RL] : ID 18 : $17.50 : Adafruit Industries, Unique & fun DIY electronics and kits
Laser Diode Driver RS232 to USB Converter
Keyspan RS232 to USB-A Adapter, DB9, 3-ft Cable | Eaton
RS232 to USB Adapter Cable, 5-ft | Eaton
Amazon.com: TRENDnet USB to Serial 9-Pin Converter Cable, Connect a RS-232 Serial Device to a USB 2.0 Port, Supports Windows & Mac, USB 1.1, USB 2.0, USB 3.0, 21 Inch Cable Length,
Mini USB 2.0 to RS-232 DB-9 Serial Adapter w/ 15kV ESD Protection & 3ft. USB Extension Cable