Black Box Async RS232 Extender over CATx - DB9 with Control Signals to Terminal Block
Gefen RS-232 Serial Extender
StarTech.com Serial DB9 RS232 Extender over Cat 5 - Up to 3300 ft (1000 meters)
Tripp Lite by Eaton Serial over Cat5/Cat6 RS232 Extender Transmitter and Receiver Up to 3280 ft. (999.74 m) TAA