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

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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
	-					or
					RXD-	AUXIN-
					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

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Contents DSC-200/300 Warranty Information Page Declaration of Conformity Manufacturers Name Address Map and Special Registers RS-422 or RS-485 Signal Line TerminationUsing the New Hardware Found Wizard Base Address and Interrupt Level IRQPage General Information Features IND Option --- Surge Suppression UpgradeHardware Configuration Factory default signal termination settingsSignal Connections Full-duplex/Half-duplex OperationEnable Scratchpad Register SPAD, J13 Clock Rate and Optional RegistersForce High-Speed Uart Clock X2, X4, or X8, J10-J12 Clock multiplier jumper optionsHardware Installation Jumper/connector locationsChannel Address Range Enabling the Special Registers Interrupt Status RegisterOptions Register Bit Name DescriptionClock Rate Multiplier RR1 RR0Windows Configuration Windows MillenniumWindows Windows Windows Page Using the New Hardware Found Wizard Windows NT DOS and Other Operating Systems QTPCI.EXEQTPCI.EXE Basic Mode display QTPCI.EXE Expert Mode display OS/2 External Connections Jumper/Channel correspondenceRTS/CTS Handshake RclkXclk AUXIN/AUXOUT LoopbackHalf-Duplex/Full-Duplex Selection Half- or full-duplex selection Termination Resistors RS-422/485 Line termination resistance valuesDSC-200/300 connector definitions RS-422/485 Peripheral ConnectionPCI Resource Map INTA#10Specifications Troubleshooting Computer will not boot upDSC-200/300 Revision June