Aalborg TIO Totalizer I/O Flow Monitor/Controller - Manual (Page 13)

9
RS-232 Communication Interface Connection:
Crossover connection must be established:
RS-232 RX
(pin 2 on the host PC DB9 connector)------pin 7 of the 9 pin "D" connector (TX-)
RS-232 TX
(pin 3 on the host PC DB9 connector)------pin 3 of the 9 pin "D" connector (RX+)
RS-232 SIGNAL GND
(pin 5 on the host PC DB9 connector)------pin 6 of the 9 pin "D" connector
RS-485 Communication Interface Connection:
The RS485 converter/adapter must be configured for: multidrop, 2 wire, half
duplex mode (See Figure 4.3). The transmitter circuit must be enabled by TD or
RTS (depending on which is available on the converter/adapter). Settings for the
receiver circuit should follow the selection made for the transmitter circuit in order
to eliminate echo.
RS-485 T(-) or R(-) ----------------- pin 7 of the 9 pin "D" connector (TX-)
RS-485 T(+) or R(+) ----------------- pin 3 of the 9 pin "D" connector (RX+)
RS-485 GND (if available) ----------------- pin 6 of the 9 pin "D" connector