
A data circuit-terminating equipment
(DCE) is a device that sits between the
data terminal equipment
Data terminal equipment (DTE) is an end instrument that converts user information into signals or reconverts received signals. It is also called data processing terminal equipment or tail circuit. A DTE device communicates with the data cir ...
(DTE) and a
data transmission circuit. It is also called data communication(s) equipment
and data carrier equipment. Usually, the DTE device is the
terminal (or
computer
A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...
), and the DCE is a
modem
The Democratic Movement (, ; MoDem ) is a centre to centre-right political party in France, whose main ideological trends are liberalism and Christian democracy, and that is characterised by a strong pro-Europeanist stance. MoDem was establis ...
.
In a ''data station'', the DCE performs functions such as
signal
A signal is both the process and the result of transmission of data over some media accomplished by embedding some variation. Signals are important in multiple subject fields including signal processing, information theory and biology.
In ...
conversion,
coding, and line clocking and may be a part of the DTE or intermediate equipment.
Interfacing equipment may be required to couple the DTE into a transmission circuit or
channel and from a transmission circuit or channel into the DTE.
Usage
Although the terms are most commonly used with
RS-232
In telecommunications, RS-232 or Recommended Standard 232 is a standard introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such as a compu ...
, several data communication standards define different types of interfaces between a DCE and a DTE. The DCE is a device that communicates with a DTE device in these standards. Standards that use this nomenclature include:
*
Federal Standard 1037C
Federal Standard 1037C, titled Telecommunications: Glossary of Telecommunication Terms, is a United States Federal Standard issued by the General Services Administration pursuant to the Federal Property and Administrative Services Act of 1949, ...
,
MIL-STD-188
MIL-STD-188 is a series of U.S. military standards relating to telecommunications.
Purpose
Faced with "past technical deficiencies in telecommunications systems and equipment and software…that were traced to basic inadequacies in the appl ...
*
RS-232
In telecommunications, RS-232 or Recommended Standard 232 is a standard introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such as a compu ...
* Certain
ITU-T
The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is one of the three Sectors (branches) of the International Telecommunication Union (ITU). It is responsible for coordinating Standardization, standards fo ...
standards in the V series (notably
V.24 and
V.35)
* Certain
ITU-T
The International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is one of the three Sectors (branches) of the International Telecommunication Union (ITU). It is responsible for coordinating Standardization, standards fo ...
standards in the X series (notably
X.21 and
X.25
X.25 is an ITU-T standard protocol suite for Packet switched network, packet-switched data communication in wide area network, wide area networks (WAN). It was originally defined by the CCITT, International Telegraph and Telephone Consultative Co ...
)
A general rule is that DCE devices provide the clock signal (internal clocking) and the DTE device synchronizes on the provided clock (external clocking).
D-sub
The D-subminiature or D-sub is a common type of electrical connector. They are named for their characteristic D-shaped metal shield. When they were introduced, D-subs were among the smallest connectors used on computer systems.
Description, ...
connectors follow another rule for pin assignment. DTE devices usually transmit on pin connector number 2 and receive on pin connector number 3. DCE devices are just the opposite: pin connector number 2 receives and pin connector number 3 transmits the signals.
When two devices, that are both DTE or both DCE, must be connected together without a modem or a similar media translator between them, a
crossover cable must be used, e.g. a
null modem for RS-232 or an
Ethernet
Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...
crossover cable.
See also
*
Networking hardware
Networking hardware, also known as network equipment or computer networking devices, are electronic devices that are required for communication and interaction between devices on a computer network. Specifically, they mediate data transmission in ...
*
Network interface device
References
External links
Data Terminating Equipment or Data Circuit-Terminating Equipment speeds IBM
{{Authority control
Data transmission
Telecommunications equipment