Quatech user manual Termination Resistors, RS-422/485 Line termination resistance values

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7.6 Termination Resistors

Line termination resistors are provided for the input signals of each of the DSCLP-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

30	DSCLP/SSCLP-200/300 User's Manual

Image 35

Contents DSCLP-200/300 Page Serial Number Declaration of Conformity Table of Contents General Information RS-422 or RS-485 Signal Line Termination Hardware ConfigurationFull-duplex/Half-duplex Operation Signal ConnectionsRCLK0SEL, RCLK1SEL J13 1 CTS0SEL, CTS1SEL J10,172 AUX0SEL1,0, AUX1SEL1,0 J12,11,19,18 Clock Rate and Optional Registers Enable Scratchpad Register SPAD, J24 TGL0SEL1,0, TGL1SEL1,0 J15,14,22,21 RXEN0SEL, RXEN1SEL J16Force High-Speed Uart Clock X2 or X4, J4-J5 Enable scratchpad registersX4 mode Jumper/connector locations Hardware InstallationBase Address and Interrupt Level IRQ Address Map and Special RegistersInterrupt Status Register Enabling the Special RegistersQuatech Modem Control Register Quatech Modem Control RegisterEnhanced Serial Adapter Identification Options RegisterRR1 RR0 Clock Rate MultiplierWindows Millennium Windows ConfigurationsWindows Windows Windows Using the New Hardware Found Wizard Viewing Resources with Device Manager Page Page Page DOS and other operating systems Other Operating SystemsWindows NT OS/2QTPCI.EXE Basic Mode display QTPCI.EXE Expert Mode display Jumper/Channel correspondence External ConnectionsRclk RTS/CTS HandshakeAUXIN/AUXOUT Loopback XclkHalf-Duplex/Full-Duplex Selection Half- or full-duplex selection RS-422/485 Line termination resistance values Termination ResistorsRS-422/485 Peripheral Connection DSCLP-200/300 connector definitionsINTA# PCI Resource MapWith 64-byte FIFOs optional SpecificationsComputer will not boot up TroubleshootingDSCLP-200/300 Revision December