RS232
USB to TTL (3.3V) Serial Cable for RPi
Deluxe Serial Adapter (Kit)
Serial Device Server Module (IPv4/IPv6)
RS232 Serial Device Server (IPv4/IPv6)
Dual RS232 Ethernet converter
SparkFun Beefy 3 - FTDI Basic Breakout
Pololu USB AVR Programmer v2.1
SparkFun Serial Basic Breakout - CH340G
USB to TTL Serial Cable
MAX3232 Breakout
TTL-232R USB 5V cable 5V IO
TTL-232R USB 5V cable 3.3V IO
LAWICEL - FTDI FT232 Basic BoB
FTDI Basic Breakout - 5VDC
FTDI Basic Breakout - 3.3VDC