Connect Tech Multi-port Serial Adapter Jumper Configuration

BlueStorm/LP Installation Guide, Connect Tech Inc.

Jumper Configuration

In the following example, the four RS-422/485 ports are set as follows: port 1 is set for half duplex, port 2 is set for half duplex; port 3 is set for full duplex, and port 4 is set for multi-drop slave.

	JA		JB		JC		JD
JD1		JD1		JD1		JD1		TxD control
JD2		JD2		JD2		JD2		RxD control
JD3		JD3		JD3		JD3		RxD ± Termination/Bias
JD4		JD4		JD4		JD4		RxD ± Termination/Bias
JD5		JD5		JD5		JD5		TxD ± Termination
	Port 1		Port 2		Port 3		Port 4

Figure 4: Jumper configuration example for 4 port RS-232/422/485 models

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 its own data as it sends. 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 150 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. The two jumpers for RxD termination/bias must be installed and removed as a pair.

TxD ± Termination

Install this jumper to enable a 150 ohm resistor across the TxD+ and TxD- pins of the corresponding port.

Auto 485 (2 port RS-422/485 models only):

Install this jumper to tri-state the RS-485 transmitters when the computer boots or is reset. Note that this jumper can be overridden by driver/software with RS-485 support. For example, the RS-485 modes in the Windows control panel will take precedence over this jumper.

Note also that Auto 485 is a single jumper. The second site is not in use. See Figure 1 for the location of this jumper.

Half Duplex and Multi-drop Slave modes require you to select the appropriate mode via software. Please refer to the readme.txt files found in the appropriate directories on the BlueStorm/LP CD.

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