Quatech RS-485 user manual RTS/CTS Handshake, Jumpers J10-12

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7 External Connections

The DSC-200/300 provides four differential communication signals per channel. The two output signals are Transmit Data (TxD) and Auxiliary Output (AUXOUT). The two input signals are Receive Data (RxD) and Auxiliary Input (AUXIN). A ground signal is also provided.

The available input signals for AUXIN are Clear To Send (CTS) and the Receive Clock (RCLK). The available output signals for AUXOUT are Request To Send (RTS), the Transmit Clock (TCLK), and the AUXIN signal (for loopback). Either half-duplex or full-duplex operation can be selected for each communications channel. Auto-Toggle is also jumper selectable .If half-duplex operation is selected, one of the UART's signals (either DTR or RTS) is used to enable the transmitter drivers. The inverse of the transmitter enable can be used to enable the receiver drivers.

Configuration is done using jumpers J10 through J23 for interface signal routing. Each jumper block provides the same functions for its particular channel. All below examples are for Channel 1. Channel 2 is the same but different sets of jumpers. See Figure 15 for Channel 2 jumpers.

Channel

Signal routing

Port 1

J10-16

 

 

Port 2

J17-23

 

 

Figure 15 --- Jumper/Channel correspondence

7.1 RTS/CTS Handshake

Transmission of RTS, combined with reception of CTS, allows for hardware handshaking (data flow control) between the UART and the external device. RTS is transmitted on AUXOUT by not connecting pins 1 and 2 of the jumper blocks J11-12. CTS is received on AUXIN by not connecting pins 1 and 2 of the jumper block J10. If RTS/CTS handshaking is not desired, the RTS output can be looped back to the CTS input by connecting pins 1 and 2 of the jumper block J10. Figure 16 shows how to select the RTS/CTS mode.

Jumpers J10-12

J10 CTS0_SEL

J11 AUX0_SEL0

J12AUX0_SEL1

Transmit RTS on AUXOUT Receive CTS on AUXIN

J10 CTS0_SEL

J11 AUX0_SEL0

J12AUX0_SEL1

Loopback RTS to CTS

Figure 16 --- RTS/CTS selection

Quatech DSC-200/300 User's Manual

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Contents DSC-200/300 Date of Purchase Model Number Page Declaration of Conformity 4 TGL0SEL1,0, TGL1SEL1,0 J15,14,22,21 IND Option --- Surge Suppression UpgradeChanging Resource Settings with Device Manager 2 AUX0SEL1,0, AUX1SEL1,0 J12,11,19,18Half-Duplex/Full-Duplex/Auto-Toggle Selection External ConnectionsGeneral Information DSC-200/300 Product Series Summary FeaturesFull-duplex/Half-duplex Operation Signal ConnectionsJumpers J10-J23 define the options for this card RXEN0SEL, RXEN1SEL J16 1 CTS0SEL, CTS1SEL J10,17RCLK0SEL, RCLK1SEL J13 Clock Rate and Optional Registers Enable Scratchpad Register SPAD, J2Clock multiplier jumper options Hardware Installation Base Address and Interrupt Level IRQ Interrupt Status Register Enabling the Special RegistersQuatech Modem Control Register Quatech Modem Control RegisterBit Name Description Options RegisterRR1 RR0 Clock Rate MultiplierWindows 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 DOS and other operating systems OS/2QTPCI.EXE QTPCI.EXE Expert Mode display Jumpers J10-12 RTS/CTS HandshakeTclk RclkAUXIN/AUXOUT loopback AUXIN/AUXOUT LoopbackHalf/full-duplex and Auto-Toggle selection RS-422/485 Termination Termination ResistorsRS-422/485 Peripheral Connection DSC-200/300 connector definitionsPCI Resource Map Specifications Computer will not boot up