Serial Communication Converters & Adapters Instruction Manual
29
PDA7485 RS-232 TO RS-422/485 CONVERTER
P R E C I S I O N D I G I T A L
Description
The PDA7485 converts unbalanced, full-duplex RS-232 signals to ba-
lanced, full or half-duplex RS-422 or RS-485 signals.
The RS-232 port, configured as a DTE port, has a female DB9 connec-
tor with pins 2 (RX output), 3 (TX input), and 5 (Signal Ground). Pins 7
(RTS) and 8 (CTS) are tied together, and pins 1 (CD), 4 (DTR), and 6
(DSR) are tied together. The RS-485 terminal blocks support Transmit
Data (DO) and (/DO), Receive Data (DI) and (/DI), and Signal Ground.
A separate terminal block supports the power input (+12VDC) and pow-
er ground (GND).
Baud rates are automatic and handled by the PDA7485.
The PDA7485 has three diagnostic LEDs: a Power (P) LED to show
when the converter is powered properly, a Transmit Data (TX) LED to
show when the converter is sending data out from the PC side, and a
Receive Data (RX) LED to show when the converter is receiving data
from the network side.
The DIP switch SW1 is located between the screw terminal connectors
and allows for system configurations.
