Amazon.com: Tripp Lite 1-Port USB to Serial Adapter Converter, RS-422/RS-485 USB to DB9, Built-in FTDI Chipset (U208-001-IND) : Everything Else
4-Port USB to RS-232 Hub - UC2324, ATEN Converters | ATEN Corporate Headquarters
Amazon.com: USB to RS422 RS485 2 Port Plug-and-Play Adapter Converter ATEN UC485, up to 921.6 Kbps, Supports Windows Vista / 7 and Above, Mac and Linux, Terminal/Echo Mode by Mode, UK, 1