Quatech DS-102 user manual External Connections

Page 16

V.EXTERNAL CONNECTIONS

RS-232-C devices are classified by their function as either Data Terminal Equipment (DTE) or Data Communication Equipment (DCE). Generally, data terminal equipment is defined as the communication source and data communication equipment is defined as the device that provides a communication channel between two DTE-type devices.

Terminal

DTE

Terminal

DTE

RS-232-C

RS-232-C

Modem

DCE

Telephone

line

Modem

DCE

Figure 10 --- Use of DTEs and DCEs in a communications link

DTE- and DCE-type devices have complementary pinouts to allow terminals and modems to be connected directly using a one-to-one cable as shown in Figure 11. In many applications, DCEs are unnecessary, and in these cases a cable called a "null modem cable" or "modem eliminator cable" is used to directly connect two DTE-type devices. A typical null modem cable is also shown in Figure 11.

(3)

RxD

 

 

 

 

 

TxD

(3)

(3)

RxD

 

 

 

 

 

 

 

 

 

 

 

 

 

RxD

(3)

 

 

 

 

 

 

 

 

 

(2)

TxD

 

 

 

 

 

RxD

(2)

(2)

TxD

 

 

 

 

 

 

 

 

 

 

 

 

 

TxD

(2)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(4)

RTS

 

 

 

 

 

CTS

(4)

(4)

RTS

 

 

 

 

 

 

 

 

 

 

 

 

 

RTS

(4)

 

 

 

 

 

 

 

 

 

 

 

(5)

CTS

 

 

 

 

 

RTS

(5)

(5)

CTS

 

 

 

 

 

 

 

 

 

 

 

 

 

CTS

(5)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(20) DTR

 

 

 

 

 

DSR

(20)

(20) DTR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DTR (20)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(6)

DSR

 

 

 

 

 

DTR

(6)

(6)

DSR

 

 

 

 

 

 

 

 

 

 

 

 

 

DSR (6)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(8)

DCD

 

 

 

 

 

DCD

(8)

(8)

DCD

 

 

 

 

 

 

 

 

 

 

 

 

DCD (8)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(22)

RI

 

 

 

 

 

RI

(22)

(22)

RI

 

 

 

 

 

 

 

 

 

 

 

 

RI

(22)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(7)

GND

 

 

 

 

 

GND (7)

(7)

GND

 

 

 

 

 

 

 

 

 

 

 

 

GND (7)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Typical DTE-to-DCE cable

 

Typical DTE-to-DTE null modem cable

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 11 --- Cabling requirements for RS-232-C devices (cables using 25-pin connectors shown)

10

Quatech DS-102 User's Manual

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Page 15 Page 17
Contents DS-102 Page IV. Setting Interrupt Levels Irqs VII. Specifications VIII. TroubleshootingTable of Contents External Connections VI. Serial Port Functional DescriptionPage Date of Purchase Model Number Page General Information Port Address IRQ Enabled ? Diagram of DS-102 Setting the address Examination of a serial port base addressSerial 1 uses SW1 Serial 2 uses SW2 Enabling or disabling ports Recommended addresses for serial ports This page intentionally left blank Serial Interrupt Sharing Channel Connection Interrupt OperationExternal Connections J7 -- Serial J8 -- Serial DS-102 connector definitions for RS-232-C This page intentionally left blank VI. Serial Port Functional Description Accessing the Serial Port registers DlabInterrupt Enable Register Interrupt Identification RegisterInterrupt Identification Register bit definitions Fifo Control Register 16550 only RXT0Line Control Register Stkp EPS PEN ParityModem Control Register Are being usedLine Status Register Line Status Register bit definitionsModem Status Register Scratchpad RegisterFifo Interrupt Mode Operation 16550 Uart only When the receiver Fifo and receiver interrupts are enabledFifo polled mode operation 16550 Uart only Factory default Baud Rate Selection026 VII. Specifications 16450 16550 optionalComputer will not boot up
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