Amazon.com: USB to DB9 RS232 Serial Adapter Converter Cable with FTDI Chip 6ft Support Win10/8/7/XP/Android/Mac/Linux/Vista (Type C to DB9) : Electronics
GitHub - mik3y/usb-serial-for-android: Android USB host serial driver library for CDC, FTDI, Arduino and other devices.
Serial OTG. Arduino CH340. FTDI. rkl099's Extension - Tutorials and Guides - MIT App Inventor Community
UsbSerial for Android | felhr85
USB to serial converter drivers for Android revisited – re-ws.pl
GitHub - ClusterM/usb-serial-telnet-server: Android application that binds a USB serial converter to a Telnet client