RS422I-PA Manual
1-2
Manual 00650-519-1
Auto and Manual Transceiver Control
RS485 communications requires the transmitter driver to be enabled and disabled as needed, to
allow all cards to share the communications line. The RS422I-PA card has automatic driver
control. When the card is not transmitting, the receiver is enabled and the transmitter driver is
disabled. Under automatic control, when data are to be transmitted, the receiver is disabled and the
driver is enabled. After data transfer is complete, the driver remains enabled for the transmission
time of one additional character and then disabled. The RS422I-PA automatically adjusts it's
timing to the baud rate of the data.
Communication Modes
Model RS422I-PA supports Half-Duplex, and Full-Duplex communications in a variety of 2-wire
and 4-wire cable connections. Half-Duplex allows traffic to travel in both directions, but only one
direction at a time. In Full-Duplex mode data travels in both directions at the same time.
CE Marking
If your card is marked CE-marked it meets requirements of EN50081-1:1992 (Emissions),
EN50082-1:1992 (Immunity), and EN60950:1992 (Safety).
