Omega OMG-USB-SER-4, Four Port RS-232/422/485 to USB Adaptor manual Switch Examples, SW3

Configuration

Switch Examples

SW1

	OFF	ON
485 3	1
	2
NE 3
485 4	3
	4
NE 4

4851 NE 1

4852 NE 2

SW3

OFF	ON
1
2
3
4

Figure 2: RS422/485 Interface Configuration

485Mode Selection OFF : 422 Mode

The transmitter lines TX+ and TX- are always driven

ON : 485 Mode

The transmitter lines TX+ and TX- are switched to high impedance when the device is not actively transmitting data

NE 485 option, OFF for 422

OFF : The receiver is always enabled. In a two -wire setup the receiver will echo back all transmitted data.

ON : The receiver is disabled when the transmitter is enabled. In a two-wire setup the receiver will not echo back transmitted data.

Note: Switch positions 1 and 2 are for port 1 and switch positions 3 and 4 for port 2 on SW3. Switch positions 1 and 2 are for port 3 and switch positions 3 and 4 for port 4 on SW1.

OMG-USB-SER-4 Page 6