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RS232
This model supports RS232 with a male 9-pin DSUB:
Pin 1: NC, not connected
Pin 2: RD, input, receive data
Pin 3: TD, output, transmit data
Pin 4: DTR, output, data terminal ready
Pin 5: GND, ground
Pin 6: DSR, input, data set ready
Pin 7: RTS, output, request to send
Pin 8: CTS, input, clear to send
Pin 9: NC, not connected
The model is designed to operate as a DTE (Data Terminal Equipment). When
connecting the gateway to a DCE (Data Communication Equipment), e.g. a modem,
a regular modem cable, straight cable, shall be used. When connecting the gateway
to another DTE, e.g. a PC, a crossover serial cable must be used. The crossover
cable must have TD and RD crossed (pins 2-3 and 3-2), RTS and CTS crossed (pins
7-8 and 8-7) and optionally DTR and DSR crossed (pins 4-6 and 6-4).
Figure 4.
Crossover cable
Figure 5.
Straight cable