Black Box DIN Rail Repeaters with Opto-Isolation, RS-422/RS-485Quick Facts Act as repeaters, isolators, and extenders. The RS 422 RS 485 model isolates RS 422 485 equipment, features selectable rates between 2400 bps and 115. 2 kbps, and enables a system to exceed 32 node limitations. The RS 232 model isolates the TD, RD, RTS, and CTS channels, supports 115. 2 kbps speeds on all four channels, and extends the RS 232 signal beyond 50 feet (15. 2 m).