Black Box RS422/485 Setting, Dual- And Quad-Portusb Hubs, Switch, Description, RS-485, RS-422

DUAL- AND QUAD-PORT USB HUBS

Table 4-7 (continued). DIP-switches SW2 and SW4 settings.

Switch	Switch		Port	Description		RS-485	RS-422
Setting	Number
PD	SW4-9	2	1K Pull	-Down	ON	OFF
PU	SW4-10	2	1K Pull-Up		ON	OFF

L = Loops TX+ to RX+ for two-wire operation.

T = Adds a 120-ohm termination resistor between RX+ and RX-.

PU = Pull-up. Adds a 1 K-ohm pull-up resistor to RX+.

PD = Pull-down. Adds a 1 K-ohm pull-down resistor to RX-.

Switch SW1 and SW3 Settings

To select RS-485 mode (4-wire or 2-wire operation) or RS-422 mode (4-wire operation), set the DIP switches labeled SW1 and SW3 on the circuit board. (See Figure 4-6 and Table 4-8.)

Figure 4-6. RS-422/485 interface configuration.

NOTE

Switch positions SW3-1 and 2 are for Port 1, and switch positions SW3-3 and 4 are for Port 2. Switch positions SW1-1 and 2 are for Port 3, and switch positions SW1-3 and 4 are for Port 4.

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