Operates in half- or full-duplex over two or four wires. Works with or without transmit "echo." Also available in four other configurations. See Similar Products. The Async RS-232 to RS-485 Interface Bidirectional Converter, DB9 Female to DB9 Female, features a DB9 female connector on the RS-232 side, and a DB9 female on the RS-485 side. It converts your unbalanced RS-232 signals to balanced half-duplex RS-485 signals.