Amazon.com: COMMFRONT Industrial USB Isolator, USB 2.0 5000Vrms Isolation (per UL 1577), Low and Full Speed Data Rate: 1.5Mbps and 12Mbps, Plug-n-Play, No Drivers Required : Electronics
USB to RS485 Isolated adapter / converter
SP385A-R3, USB to RS232 Opto-Isolated Converter - Black Box
USB-ISOLATOR - Single Port USB Isolator - ACCES I/O Products
Hifimediy USB Isolators - Made for audio to prevent ground loops
Optically Isolated 7-Port USB Hub - Sealevel
Amazon.com: StarTech.com USB to Serial Adapter - Optical Isolation - USB Powered - FTDI USB to Serial Adapter - USB to RS232 Adapter Cable (ICUSB2321FIS),Black : Electronics
USB to Serial Adapter Cable w/ Isolation - Serial Cards & Adapters | StarTech.com
2-Port Industrial USB 2.0 to RS-422 / 485 Optical Isolated Adapter - Coolgear
USB TO RS232/RS422/RS485 ADAPTERS W/OPTICAL ISOLATION (FULL SPEED) — Connective Peripherals - Global Store
Optically Isolated 7-Port USB Hub - Sealevel
Optically Isolated 7-Port USB Hub with SeaLATCH USB Ports - Sealevel
4 Port RS-232 USB to Serial Adapter w/ Optical Isolation & Surge Protection - Coolgear
Black Box Industrial-Grade USB Hub - hub - 4 ports - ICI200A - Power Supplies - CDW.com
USB TO RS232 ADAPTERS W/OPTICAL ISOLATION (FULL SPEED) — Connective Peripherals - Global Store
Adafruit USB Isolator - 100mA Isolated Low/Full Speed USB : ID 2107 : $34.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Optically Isolated 7-Port USB Hub with SeaLATCH USB Ports - Sealevel