Connect Tech Xtreme/104-Express User Manual

Figure 3: Example port configuration jumper block settings

NOTE: The example above illustrates the following:

Ports 1, 2, 3 and 4 are configured for RS-485 Half-Duplex

Ports 5 and 6 are configured for RS-485 Multi-Drop Slave

Ports 7 and 8 are configured for RS-232

RS-485 Selection: Install this jumper to configure a port for RS-422/485 mode. If the jumper is not installed, the port will function in RS-232 mode. All jumpers should be removed from any port operating in RS-232 mode.

TxD Control: Install this jumper to enable the RS-485 transmitter only when sending data. This mode is useful for half-duplex operation when only one device is allowed to send data at a time. If the jumper is not installed, the transmitter will always drive the line to an idle state when not sending data.

RxD Control: Install this jumper to enable the RS-485 receiver only when NOT transmitting data. This is useful for half-duplex operation to prevent the transmitting device from receiving the data it has sent. If this jumper is not installed, the receiver is always enabled and ready to receive data.

RxD ± Termination/Bias: Install this pair of jumpers to enable a 120 Ohm terminator across the RxD+ and RxD- pins for the corresponding port. A biasing network is also enabled that drives the receiver to an inactive or safe mode. The receiver can still receive data from another device and the biasing helps to prevent the reception of data generated by noise on the transmission line, or a disconnected line. The two jumpers for RxD termination/bias must be installed and removed as a pair.

TxD ± Termination: Install this jumper to enable a 120 Ohm resistor across the TxD+ and TxD- pins of the corresponding port.

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Connect Tech 104 user manual Example port configuration jumper block settings