Tibbo Technology Inc

RS485 port

This port has only +/-RX and +/-TX signal pairs. If you are working in the half-duplex mode, connect +RX to +TX, and -RX to -TX. This will allow your system to communicate over a single twisted pair. Direction control is through the RTS line — the line shall be LOW for data input and HIGH for output. Keep the RX and TX pairs separate for the full-duplex mode and set the RTS line HIGH to keep the TX enabled at all times.

There are three LEDs: two red and one green. Red LEDs are connected to TX and OUT/-IN lines. The green LED is for the RX input. All LEDs are buffered (with logic gates) and light up for the LOW state of control lines. Revision B devices are marked by a small round sticker with letter "B". The sticker is on the side of the Tibbit.