Call control
Encyclopedia
In telephony
, call control refers to the software
within a telephone switch that supplies its central function. Call control decodes addressing information and routes telephone call
s from one end point to another. It also creates the features that can be used to adapt standard switch operation to the needs of users. Common examples of such features are "Call Waiting
", "Call Forward on Busy
", and "Do Not Disturb".
Call control software, because of its central place in the operation of the telephone network, is marked by both complexity and reliability. Call control systems will typically require many thousands of person years in development. They will contain millions of lines of high level code. However they must and do meet reliability requirements that specify switch down time of only a few minutes in forty years.
The required functionality and reliability of call control is a major challenge for Voice over IP
(VoIP) systems. VoIP systems are based on Internet
standards and technology which have not previously attempted to satisfy such complex and demanding requirements as those that specify call control.
An alternative name often used is call processing
.
Telephony
In telecommunications, telephony encompasses the general use of equipment to provide communication over distances, specifically by connecting telephones to each other....
, call control refers to the software
Computer software
Computer software, or just software, is a collection of computer programs and related data that provide the instructions for telling a computer what to do and how to do it....
within a telephone switch that supplies its central function. Call control decodes addressing information and routes telephone call
Telephone call
A 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...
s from one end point to another. It also creates the features that can be used to adapt standard switch operation to the needs of users. Common examples of such features are "Call Waiting
Call waiting
Call waiting , in telephony, is a feature on some telephone networks. If a calling party places a call to a called party which is otherwise engaged, and the called party has the call waiting feature enabled, the called party is able to suspend the current telephone call and switch to the new...
", "Call Forward on Busy
Call forwarding
Call forwarding , in telephony, is a feature on some telephone networks allowing an incoming call to a called party to be redirected to a third party. For example, the third party may be a mobile telephone, voicemail box or other telephone number where the desired called party is situated. It was...
", and "Do Not Disturb".
Call control software, because of its central place in the operation of the telephone network, is marked by both complexity and reliability. Call control systems will typically require many thousands of person years in development. They will contain millions of lines of high level code. However they must and do meet reliability requirements that specify switch down time of only a few minutes in forty years.
The required functionality and reliability of call control is a major challenge for Voice over IP
Voice over IP
Voice over Internet Protocol is a family of technologies, methodologies, communication protocols, and transmission techniques for the delivery of voice communications and multimedia sessions over Internet Protocol networks, such as the Internet...
(VoIP) systems. VoIP systems are based on Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
standards and technology which have not previously attempted to satisfy such complex and demanding requirements as those that specify call control.
An alternative name often used is call processing
Call processing
In telecommunication, the term call processing has the following meanings:# The sequence of operations performed by a switching system from the acceptance of an incoming call through the final disposition of the call...
.