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What Do DTE and DCE Mean in Serial Communication?

Hardware: Serial, Serial>>RS-232

Problem:
My National Instruments manual mentions DTE and DCE, but it does not describe the terms in detail. What do these terms mean?

Solution:
DTE means Data Terminal Equipment; DCE means Data Communications Equipment.

More specifically, DTE and DCE are the two sides of an RS-232 interface. It is important to differentiate between DTE and DCE devices because the pinouts for cables are physically different, as are the descriptions of handshaking and interfacing. A modem is an example of a DCE device.  A common DTE device is the serial port of a computer.

Wiring a DTE device to a DCE device for communication is easy.  The pins are a one-to-one connection, meaning all wires go from pin x to pin x.  A straight through cable is commonly used for this application.  In contrast, wiring two DTE devices together requires crossing the transmit and receive wires.  This cable is known as a null modem or crossover cable.

For more information on cabling and serial protocol, please see the documents linked below.

Related Links:
NI Developer Zone: Serial Communication Starting Point
Product Manuals: Serial Hardware and Software for Windows User Manual
KnowledgeBase 2N8IEAYF: Auto232 Mode Doesn't Select the Proper RS-232 Transceiver Mode
KnowledgeBase 3GLDMSIT: What is the Difference Between Null Modem and Straight Through Serial Cables?

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Report Date: 01/31/2000
Last Updated: 08/30/2007
Document ID: 1TU953QR

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