Black Box RS422/485, RS-232/422/485 manual Switch SW1 and SW3 Settings

DUAL- AND QUAD-PORT USB HUBS

Table 4-4. DIP-switches SW2 and SW4 settings.

Switch	Switch		Port		Description		RS-485	RS-422
Setting	Number
L	SW2-1	3		TX+	to RX+	ON	OFF
L	SW2-2	3		TX-	to RX-	ON	OFF
T	SW2-3	3		Termination		ON	ON
PD	SW2-4	3	1K Pull-Down			ON	OFF
PU	SW2-5	3	1K Pull-Up			ON	OFF
L	SW2-6	4		TX+ to RX+		ON	OFF
L	SW2-7	4		TX- to RX-		ON	OFF
T	SW2-8	4		Termination		ON	ON
PD	SW2-9	4	1K Pull-Down			ON	OFF
PU	SW2-10	4	1K Pull-Up			ON	OFF
L	SW4-1	1		TX+ to RX+		ON	OFF
L	SW4-2	1		TX- to RX-		ON	OFF
T	SW4-3	1		Termination		ON	ON
PD	SW4-4	1	1K Pull-Down			ON	OFF
PU	SW4-5	1	1K Pull-Up			ON	OFF
L	SW4-6	2		TX+ to RX+		ON	OFF
L	SW4-7	2		TX- to RX-		ON	OFF
T	SW4-8	2		Termination		ON	ON
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 4-4 and Table 4-5.)

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