Amazon.com: Plugable USB to Serial Adapter Compatible with Windows, Mac, Linux (RS-232/DB9 DTE Male Connector, Prolific PL2303HX Rev. D Chipset) : Electronics
USB to RS232 - USB232 - Fixed Length USB Cable – Grid Connect
UC2322 - 2-Port USB-to -Serial RS-232 Hub
USB RS-232 Industrial Adapter Isolated and Surge Protected FTDI Chip
ATEN CE820-ATA-G: KVM Extender Set, HDMI, 100 m at reichelt elektronik
4 Port Professional RS-232 USB 2.0 to Serial Adapter
Amazon.com: CBL-USB-232: USB to RS232 Converter Cable with Thumscrews, 1.1m long (Prolific PL2303) : Electronics
FTDI Serial TTL-232 USB Type C Cable - 3V Power and Logic : ID 4331 : $19.95 : Adafruit Industries, Unique & fun DIY electronics and kits
USB 2.0 RS-232 Serial Adapter with LED Indicators
SCHOTT RS 232 USB 1.1 Converter
ATEN USB Type-A Male to RS-232/DB-9 Serial Male Adapter UC232A