Quatech DSCLP-100 user manual External Connections

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7 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

Modem

DCE

Telephone line

Figure 16 --- 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 16. 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 16.

(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 17 --- Cabling requirements for RS-232-C devices

(cables using 25-pin connectors shown)

DSCLP/SSCLP-100 User's Manual

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Contents DSCLP/SSCLP-100 Page Date of Purchase Model Number Declaration of Conformity Table of Contents General Information Enable Scratchpad Register SPAD, J2 Hardware ConfigurationFactory Default Configuration Force High-Speed Uart Clock X2 or X4, J4-J5Clock multiplier jumper options Hardware Installation Jumper/connector locationsThis page intentionally blank Address Map and Special Registers Base Address and Interrupt Level IRQEnabling the Special Registers Interrupt Status RegisterOptions Register Enhanced Serial Adapter IdentificationClock Rate Multiplier RR1 RR0Windows Configurations Windows MillenniumWindows Windows Windows Using the New Hardware Found Wizard Viewing Resources with Device Manager Page Page Page OS/2 Other Operating SystemsWindows NT DOS and other operating systemsQTPCI.EXE Basic Mode display QTPCI.EXE Expert Mode display External Connections RS-232 Port Signal PCI Resource Map INTA#Specifications ICL3245CAPage Troubleshooting Computer will not boot upSSCLP/DSCLP-100