Quatech DSC-300, DSC-200 Termination Resistors, RS-422/485 Line termination resistance values

8.6 Termination Resistors

Line termination resistors are provided for the input signals of each of the DSC-200/300's RS-422/485 ports. Termination may be selected or removed for individual signal lines using jumper blocks J1-J4.

	RS-422 Rt = 100 ohm 1/2W
	RS-485 Rt = 120 ohm 1/2W
RS-422/485 Receiver
+		RXD+	AUXIN+
	Rt
			or
-
		RXD-	AUXIN-

Jumpers J1-J4

3	3	3
2	2	2
1	1	1
no termination	RS-422 termination	RS-485 termination
	(100 ohms)	(120 omhs)

(factory default)

Figure 25 --- RS-422/485 Line termination resistance values

Quatech DSC-200/300 User's Manual 34