Serial Extender over Cat 5 Up to 3300 ft - Serial Over IP Cat5/6 Extenders | StarTech.com
SPIDER Automation™ 【USB to RS232 Converter】 High-Speed Serial DB9 male Cable 1-port Adapter, CE FCC RoHS Certified, Based on (industrial FTDI Chipset), 1 meter cable length | by SPIDER Automation : Amazon.in:
RS-232 Bus Description and EIA232 Pinout
RS232 Repeater, Extend up to 4000 FT with this RS232 Extender
RS232 VS RS485- Know the Difference(Pinout, Speed)