Quatech RS-485 user manual Used when external handshaking or

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Used when external handshaking or

 

 

clocking signals are not available.

 

 

RTS routed to AUXOUT, AUXIN

Modem Control

 

routed to CTS, and TCLK routed to

 

RCLK. Used when RTS/CTS

 

 

 

 

handshaking is required.

 

 

RTS routed to CTS, AUXIN routed to

 

 

RCLK, and TCLK routed to AUXOUT.

Clocks

 

Used to connect ports transmitting at

 

different baud rates. In order to

 

 

 

 

function, all ports must have and use

 

 

this feature.

 

Receive Control

 

 

Receivers are always enabled. In a Half

Always Receive

 

Duplex mode, you will receive what you

 

 

transmit (sometimes called echo).

 

 

Receivers are only enabled when not

When NOT Tranmitting

 

transmitting. In a Half Duplex mode,

 

 

you will not receive what you transmit.

RS-422/485 Duplex Mode

 

 

Transmitters and receivers are always

Full Duplex

 

enabled; ports can send and receive

 

simultaneously. Used in four-wire

 

 

 

 

communication.

Half Duplex using RTS

 

RTS is set to enable the transmitters.

 

Used in two-wire communication.

 

 

Half Duplex using DTR

 

DTR is set to enable the transmitters.

 

Used in two-wire communication

 

 

 

 

Hardware automatically enables the

 

 

transmitters when transmitting.

Auto Toggle

 

Transmitters will turn off three bit-times

 

after the last stop bit of the last

 

 

 

 

character, regardless of baud rate. Used

 

 

in two-wire communication.

8.To summarize the RS-422/485 output drivers enable options: The DSC-200/300’s ports may be configured for either full duplex or half duplex operation with this option. The default setting is the RS-422/485 ports are configured for full duplex operation with the RS-422/485 output drivers always enabled. In half duplex mode, the RS-422/485 transmitter may be enabled and disabled via the RTS (request to send) or DTR (data terminal ready) signals, or in auto-toggle mode, set to enable only when data is being transmitted. Both RTS and DTR are controlled through the Modem Control Register of the 16550.

Quatech DSC-200/300 User's Manual

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Contents DSC-200/300 Date of Purchase Model Number Page Declaration of Conformity 2 AUX0SEL1,0, AUX1SEL1,0 J12,11,19,18 IND Option --- Surge Suppression UpgradeChanging Resource Settings with Device Manager 4 TGL0SEL1,0, TGL1SEL1,0 J15,14,22,21External Connections Half-Duplex/Full-Duplex/Auto-Toggle SelectionGeneral Information Features DSC-200/300 Product Series SummarySignal Connections Full-duplex/Half-duplex OperationJumpers J10-J23 define the options for this card 1 CTS0SEL, CTS1SEL J10,17 RCLK0SEL, RCLK1SEL J13RXEN0SEL, RXEN1SEL J16 Enable Scratchpad Register SPAD, J2 Clock Rate and Optional RegistersClock multiplier jumper options Hardware Installation Base Address and Interrupt Level IRQ Enabling the Special Registers Interrupt Status RegisterQuatech Modem Control Register Quatech Modem Control RegisterOptions Register Bit Name DescriptionClock Rate Multiplier RR1 RR0Windows Millennium Windows Windows Windows Windows NT Viewing Resources with Device Manager Quatech DSC-200/300 PCI Two-Port RS-422/RS485 Serial Adapter Adapter Data Rate Multiplier Application. This mode is useful for legacy Used when external handshaking or Page OS/2 DOS and other operating systemsQTPCI.EXE QTPCI.EXE Expert Mode display RTS/CTS Handshake Jumpers J10-12Rclk TclkAUXIN/AUXOUT Loopback AUXIN/AUXOUT loopbackHalf/full-duplex and Auto-Toggle selection Termination Resistors RS-422/485 TerminationDSC-200/300 connector definitions RS-422/485 Peripheral ConnectionPCI Resource Map Specifications Computer will not boot up