USB to 9 Pin RS232 Converter | Makerfabs Electronics
Serial Ethernet Converter (RS232, RS485, RS422) Industrial Panel Mount, 2 Ports - Pro [USC-HF5122] - $149.00 : Serial Data Communication by U.S. Converters LLC
AK-RS232 – TTL to RS232 Converter | Artekit Labs
LM060-0613 Lm Technologies, Adapter, USB/RS232-Wandler, FTDI | Farnell DE
RS232 to RS422 Converter, Large Selection of Reliable RS422 Converters
AK-RS232-LED – TTL to RS232 converter with LEDs | Artekit Labs