Aalborg DFC Digital - Manual (Page 6)

RS-485 option:
The RS485 converter/adapter has to be configured for: multidrop, 2 wire, half duplex
mode. The transmitter circuit has to be enabled by TD or RTS (depending on which
is available on the converter/adapter). Settings for the receiver circuit usually should
follow the selection made for the transmitter circuit in order to eliminate Echo.
Pin 11 (-) of the “D” connector has to be connected to
T- or R- on the RS-485 converter/adapter.
Pin 24 (+) of the “D” connector has to be connected to
T+ or R+ on the RS-485 converter/adapter.
Pin 20 (Common) of the “D” connector has to be connected
to GND on the RS-485 converter/adapter.
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