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Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed. | A duplex communication system is a system composed of two connected parties or devices which can communicate with one another in both directions. (The term duplex is not used when describing communication between more than two parties or devices.) Image File history File links Question_book-3. ...
Duplex systems are employed in nearly all communications networks, either to allow for a communication "two-way street" between two connected parties or to provide a "reverse path" for the monitoring and remote adjustment of equipment in the field.
Half-Duplex
A simple illustration of a half-duplex communication system. A half-duplex system provides for communication in both directions, but only one direction at a time (not simultaneously). Typically, once a party begins receiving a signal, it must wait for the transmitter to stop transmitting, before replying. Image File history File links Size of this preview: 462 × 316 pixelsFull resolution (462 × 316 pixel, file size: 17 KB, MIME type: image/jpeg) A simple illustration of a half-duplex communication system. ...
Image File history File links Size of this preview: 462 × 316 pixelsFull resolution (462 × 316 pixel, file size: 17 KB, MIME type: image/jpeg) A simple illustration of a half-duplex communication system. ...
An example of a half-duplex system is a two-party system such as a "walkie-talkie" style two-way radio, wherein one must use "Over" or another previously designated command to indicate the end of transmission, and ensure that only one party transmits at a time, because both parties transmit on the same frequency.
A good analogy for a half-duplex system would be a one lane road with traffic controllers at each end. Traffic can flow in both directions, but only one direction at a time with this being regulated by the traffic controllers.
- Note that this is one of two contradictory definitions for half-duplex. This definition matches the ITU-T standard. For more detail, see Simplex communication.
The ITU Telecommunication Standardization Sector (ITU-T) coordinates standards for telecommunications on behalf of the International Telecommunication Union (ITU) and is based in Geneva, Switzerland. ...
A simplex communication system is one where all signals flow in one direction. ...
Full-Duplex
A simple illustration of a full-duplex communication system. A full-duplex system allows communication in both directions, and unlike half-duplex, allows this to happen simultaneously. Land-line telephone networks are full-duplex since they allow both callers to speak and be heard at the same time. A good analogy for a full-duplex system would be a two lane road with one lane for each direction. Image File history File links Size of this preview: 462 × 132 pixelsFull resolution (462 × 132 pixel, file size: 7 KB, MIME type: image/jpeg) A simple illustration of a full-duplex communication system. ...
Image File history File links Size of this preview: 462 × 132 pixelsFull resolution (462 × 132 pixel, file size: 7 KB, MIME type: image/jpeg) A simple illustration of a full-duplex communication system. ...
Examples: Telephone, Mobile Phone, etc. For other uses, see Telephone (disambiguation). ...
Two way radios can be, for instance, designed as full-duplex systems, which transmit on one frequency and receive on a different frequency. This is also called frequency-division duplex. Frequency-division-duplex systems can be extended to farther distances using pairs of simple repeater stations, owing to the fact the communications transmitted on any one frequency always travels in the same direction.
Full-duplex Ethernet connections work by making simultaneous use of all four physical pair of twisted cable (which are inside the insulation), where two pair are used for receiving packets and two pair are using for sending packets to a directly connected device. This effectively makes the cable itself a collision-free environment, and theoretically doubles the maximum bandwidth that can be supported by the connection.
Emulation of full duplex in shared physical media Where channel access methods are used in point to multipoint networks such as cellular networks for dividing forward and reverse communication channels on the same physical communications medium, they are known as duplexing methods, such as: In communications, a channel access method is used to share a communications channel or physical communications medium between multiple users. ...
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Time division duplex Time division duplex (TDD) is the application of time-division multiplexing to separate outward and return signals. It emulates full duplex communication over a half duplex communication link. Time division duplex has a strong advantage in the case where the asymmetry of the uplink and downlink data speed is variable. As the amount of uplink data increases, more bandwidth can dynamically be allocated to that and as it shrinks it can be taken away. Another advantage is that the uplink and downlink radio paths are likely to be very similar in the case of a slow moving system. This means that techniques such as beamforming work well with TDD systems. Time-division multiplexing (TDM) is a type of digital or (rarely) analog multiplexing in which two or more signals or bit streams are transferred apparently simultaneously as sub-channels in one communication channel, but physically are taking turns on the channel. ...
Symmetry is a characteristic of geometrical shapes, equations and other objects; we say that such an object is symmetric with respect to a given operation if this operation, when applied to the object, does not appear to change it. ...
Look up uplink in Wiktionary, the free dictionary. ...
In radio communications, a downlink is the link from a satellite to a ground station. ...
Beamforming is a signal processing technique used with arrays of transmitting or receiving transducers that control the directionality of, or sensitivity to, a radiation pattern. ...
Examples of TDD systems are:
W-CDMA (Wideband Code Division Multiple Access) is a type of 3G cellular network. ...
UMTS-TDD is a mobile data network standard built upon the UMTS 3G cellular mobile phone standard, using a TD-CDMA, TD-SCDMA, or other 3GPP-approved, air interface that uses Time Division Duplexing to duplex spectrum between the up-link and down-link. ...
TD-SCDMA (Time Division-Synchronous Code Division Multiple Access) is a 3G mobile telecommunications standard, being pursued in the Peoples Republic of China by the Chinese Academy of Telecommunications Technology (CATT), Datang and Siemens AG, in an attempt to develop home-grown technology and not be dependent on Western...
See http://en. ...
The IEEE 802. ...
Official WiMax logo WiMAX, the Worldwide Interoperability for Microwave Access, is a telecommunications technology aimed at providing wireless data over long distances in a variety of ways, from point-to-point links to full mobile cellular type access. ...
Wikipedia does not yet have an article with this exact name. ...
Carrier Sense Multiple Access (CSMA) is a probabilistic Media Access Control (MAC) protocol in which a node verifies the absence of other traffic before transmitting on a shared physical medium, such as an electrical bus, or a band of electromagnetic spectrum. ...
Bold text 4 port ethernet hub An Ethernet hub or concentrator is a device for connecting multiple twisted pair or fiber optic Ethernet devices together, making them act as a single segment. ...
Ethernet is a large, diverse family of frame-based computer networking technologies that operate at many speeds for local area networks (LANs). ...
It has been suggested that wireless network interface cards be merged into this article or section. ...
Bluetooth logo This article is about the electronic protocol named after Harald Bluetooth Gormson. ...
Frequency division duplex Frequency duplex means that the radio transmitter and receiver operates at different frequencies. The term is frequently used in HAM radio operation, where a HAM operator is attempting to contact a repeater station. The station must be able to send and receive a transmission at the same time, and does so by altering the frequency at which it sends and receives slightly. This mode of operation is referred to as duplex mode or offset mode. Antenna tower of Crystal Palace transmitter, London A transmitter (sometimes abbreviated XMTR) is an electronic device which with the aid of an antenna propagates an electromagnetic signal such as radio, television, or other telecommunications. ...
In radio terminology, a receiver is an electronic circuit that receives a radio signal from an antenna and decodes the signal for use as sound, pictures, navigational-position information, etc. ...
For other uses, see Frequency (disambiguation). ...
For other uses, see Repeater (disambiguation). ...
Uplink and downlink sub-bands are said to be separated by the "frequency offset". Frequency division duplex or frequency duplex is much more efficient in the case of symmetric traffic. In this case TDD tends to waste bandwidth during switch over from transmit to receive, has greater inherent latency, and may require more complex, more power-hungry circuitry. Frequency duplex means that the radio transmitter and receiver operates at different frequencies. ...
Bandwidth is the difference between the upper and lower cutoff frequencies of, for example, a filter, a communication channel, or a signal spectrum, and is typically measured in hertz. ...
Lag is a common term used to describe a symptom often encountered in computing and especially networked systems, where results of actions appear much later than expected. ...
There are many kinds of circuit An electric circuit interconnects electrical elements. ...
Another advantage of FDD is that it makes radio planning easier and more efficient since base stations do not "hear" each other (as they transmit and receive in different sub-bands) and therefore will normally not interfere each other. Conversely with TDD systems, care must be taken to keep guard bands between neighboring base stations (which decreases spectral efficiency) or to synchronize base stations so they will transmit and receive at the same time (which increases network complexity and therefore cost, and reduces bandwidth allocation flexibility as all base stations and sectors will be forced to use the same uplink/downlink ratio) Spectral efficiency or spectrum efficiency refers to the amount of information that can be transmitted over a given bandwidth in a specific digital communication system. ...
Examples of FDD systems are:
Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional modem can provide. ...
It has been suggested that VDSL2 be merged into this article or section. ...
Motorola T2288 mobile phone A mobile phone is a portable electronic device which behaves as a normal telephone whilst being able to move over a wide area (compare cordless phone which acts as a telephone only within a limited range). ...
Universal Mobile Telecommunications System (UMTS) is one of the third-generation (3G) mobile phone technologies. ...
W-CDMA (Wideband Code Division Multiple Access), a wideband spread-spectrum 3G mobile telecommuncation air interface that utilizes code division multiple access (or CDMA the general multiplexing scheme, not to be confused with CDMA the standard), is a 3G mobile communications standard allied with the GSM standard. ...
The IEEE 802. ...
Official WiMax logo WiMAX, the Worldwide Interoperability for Microwave Access, is a telecommunications technology aimed at providing wireless data over long distances in a variety of ways, from point-to-point links to full mobile cellular type access. ...
Echo cancellation Echo cancellation can also implement full duplex communications over certain types of shared media. In this configuration, both devices send and receive over the same medium at the same time. When processing the signal it receives, a transceiver removes the "echo" of the signal it sent, leaving, in theory, the other transceiver's signal only. The term echo cancellation is used in telephony to describe the process of removing echo from a voice communication in order to improve voice quality on a telephone call. ...
Echo cancellation is at the heart of the V.32, V.34, V.56 and V.90 modem standards.
Echo cancellers are available as both software and hardware solutions. They can be independent components in a communications system or integrated into the communication system's central processing unit. Devices that do not eliminate echo in the system will not produce good full duplex performance.
Examples For other uses, see Telephone (disambiguation). ...
A typical CB base station. ...
“IRC†redirects here. ...
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