Amazon.com: Ut-2212 RS232 Serial Port Extender Long line Driver Serial Port Signal Amplifier transceiver can Extend 1.2km : Electronics
RS-232 Optical Isolated Line Booster 2,500Vrms
RS232 Linea Booster Lungo-Line Ricetrasmettitore 232 Seriale Convertitore di Segnale Driver Telecamera di Rete con Isolamento Fotoelettrico ATC-155 _ - AliExpress Mobile
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RS232 Repeater
BB-232LB9R Advantech | Mouser Italia
ATC-155 RS232 Extended Pair Line Booster - Up to 7 miles (12K meters) – Grid Connect
RS-232 Optical Isolated Line Booster 2,500Vrms
AVLink RS232-E+ RS-232 extender set 1000 meters | Intronics BV
RS232 Booster. Optil 900mforForstærker
RS232 Repeater, Extend up to 4000 FT with this RS232 Extender
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RS232 Extender CAT5e CAT6 Extend Serial Device 3,935 Feet