RS-422A

The RS422A interface( EIA-422) is a bidirectional serial interface for data transfer rates ofup to 10 Mbit/s. The interface has a 9- pin sub-D connector, the maximum bridgeable distance is 1,200 m.

For transmission, the signals of the individual channels are converted into differential signals, which are transmitted symmetrically on the wire pairs of the TP cables. During this transmission, interfering signals compensate each other due to the common mode suppression. The RS422A interface has at least two channels for transmit data( TxD) and receive data( RxD), which are transmitted via two wire pairs. In addition, the common ground provides the reference for the receivers and transmitters. Handshaking signals can also be transmitted via the RS422A interface using additional wire pairs.

The signal levels at the transmitter are +5 V( TDA) and 0 V (TDB) in the active state during space.