SERIALGEAR 4-Port DB-9 RS232 to USB Adapter with Isolation and Surge Protection

Fully compatible with USB1.0 and USB 1.1; Forward compatible with USB 2.0 Supports 4 DB9-Male UART Serial ports with Data Rate from 75 bps to 921.6Kbps Supports Isolation and Surge Protection Features Power solely from USB Bus. No external power supply needed. Supports 3-wire RS232 Signals (TXD, RXD, GND)