Virtual call capability
Encyclopedia
In telecommunication
, a virtual call capability, sometimes called a virtual call facility, is a service feature in which:
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...
, a virtual call capability, sometimes called a virtual call facility, is a service feature in which:
- a callTelephone callA telephone call is a connection over a telephone network between the calling party and the called party.-Information transmission:A telephone call may carry ordinary voice transmission using a telephone, data transmission when the calling party and called party are using modems, or facsimile...
set-up procedure and a call disengagement procedure determine the period of communication between two data terminal equipmentData terminal equipmentData Terminal Equipment is an end instrument that converts user information into signals or reconverts received signals. These can also be called tail circuits. A DTE device communicates with the data circuit-terminating equipment...
s (DTEs) in which userUser (telecommunications)In telecommunications, a user is a person, organization, or other entity that employs the services provided by a telecommunication system, or by an information processing system, for transfer of information....
data are transferred by the networkTelecommunications networkA telecommunications network is a collection of terminals, links and nodes which connect together to enable telecommunication between users of the terminals. Networks may use circuit switching or message switching. Each terminal in the network must have a unique address so messages or connections...
in the packet mode of operation - end-to-end transferCall transferA call transfer is a telecommunications mechanism that enables a user to relocate an existing call to another phone or attendant console by using the transfer button and dialing the required location. The transferred call is either announced or unannounced....
control of packets within the network is required - data may be delivered to the network by the call originator before the call access phase is completed, but the data are not delivered to the call receiver if the call attempt is unsuccessful
- the network delivers all the user data to the call receiver in the same sequenceSequenceIn mathematics, a sequence is an ordered list of objects . Like a set, it contains members , and the number of terms is called the length of the sequence. Unlike a set, order matters, and exactly the same elements can appear multiple times at different positions in the sequence...
in which the data are received by the network - multi-access DTEs may have several virtual calls in progress at the same timeTimeTime is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
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