Black Box LES404A 3.2.4 RS-232 Mode, 3.2.5 RS-422 Mode, 3.2.6 RS-485H Mode, 3.2.7 RS-485F Mode

Chapter 3: Hardware Configuration

3.2.4 RS-232 Mode

In RS-232 Mode, the currently selected serial port is configured as an RS-232 interface supporting eight RS-232 signal lines plus Signal Ground and is configured as a DTE, like a computer. Signals are single-ended and referenced to Ground. To use handshaking, Flow Control must be set to RTS/CTS during configuration.

3.2.5 RS-422 Mode

In RS-422 Mode, the currently selected serial port is configured as an RS-422 interface supporting four RS-422 signal channels with full-duplex operation for Receive, Transmit, RTS (Request To Send), and CTS (Clear To Send). The data lines are differential pairs (A and B) in which the B line is positive relative to the A line in the idle (mark) state. Ground provides a common mode reference. To use handshaking, Flow Control must be set to RTS/CTS during configuration.

3.2.6 RS-485H Mode

In RS-485H Mode, the currently selected port is configured as a two-wire RS-485 interface supporting DataB(+) and DataA(-) signal channels using half-duplex operation. The data lines are differential with the Data B line positive relative to Data A in the idle (mark) state. Ground provides a common mode reference.

3.2.7 RS-485F Mode

In RS-485F Mode, the currently selected port is configured as a four-wire RS-485 interface supporting transmit lines TXDB(+) and TXDA(-) and receive lines RXDB(+) and RXDA(-) for full-duplex operation. The lines are differential with the B line positive relative to A in the idle (mark) state. Ground provides a common mode reference.

3.2.8 RS-485 Receiver Biasing

RS-485 Receiver Biasing can be implemented from the Serial Server if the network does not supply it. Remove the four screws from the cover of the Serial Server, slide the cover off, and re-position the bias jumpers as indicated in the following diagrams and tables.

NOTE: The Serial Servers provide separate jumpers for RS-485 half-duplex and RS-422/485 full-duplex operation. Also, the 1-Port Industrial Serial Server provides separate jumpers for the terminal block and DB9 connectors. Biasing jumpers are also provided for CTS inputs.

Figure 3-1. 1-Port Industrial Serial Server bias jumper locations.

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