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H.450
{{Unreferenced, date=December 2009 H.450 refers to a set of standards created by the International Telecommunication Union (ITU) to define several Supplementary Services of the packet based telecommunication protocol known as H.323. It parallels another set of standards known as QSIG which define similar services for ISDN Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Work ... based networks. * H.450.1, Supplementary Services Framework The general mechanism for delivering supplementary services is explained in this paper. Supplementary services messages are exchanged by means of ROSE (Remote Operations Service Extension). * H.450.2, Call Transfer Supplementary Service E.g. explains how a party-B can turn an active call between party-A and party-B into a call between party-A and a new p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QSIG
QSIG is an ISDN based signaling protocol for signaling between private branch exchanges (PBXs) in a private integrated services network (PISN). It makes use of the connection-level Q.931 protocol and the application-level ROSE protocol. ISDN "proper" functions as the physical link layer. QSIG was originally developed by Ecma International, adopted by ETSI and is defined by a set of ISO standard documents, so is not owned by any company. This allows interoperability between communications platforms provided by disparate vendors. QSIG has two layers, called BC (basic call) and GF (generic function). QSIG BC describes how to set up calls between PBXs. QSIG GF provides supplementary services for large-scale corporate, educational, and government networks, such as line identification, call intrusion and call forwarding. Thus for a large or very distributed company that requires multiple PBXs, users can receive the same services across the network and be unaware of the switch that their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Telecommunication Union
The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Union, making it the oldest UN agency. The ITU was initially aimed at helping connect telegraphic networks between countries, with its mandate consistently broadening with the advent of new communications technologies; it adopted its current name in 1932 to reflect its expanded responsibilities over radio and the telephone. On 15 November 1947, the ITU entered into an agreement with the newly created United Nations to become a specialized agency within the UN system, which formally entered into force on 1 January 1949. The ITU promotes the shared global use of the radio spectrum, facilitates international cooperation in assigning satellite orbits, assists in developing and coordinating worldwide technical standards, and works to improve tele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISDN
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Work on the standard began in 1980 at Bell Labs and was formally standardized in 1988 in the CCITT "Red Book". By the time the standard was released, newer networking systems with much greater speeds were available, and ISDN saw relatively little uptake in the wider market. One estimate suggests ISDN use peaked at a worldwide total of 25 million subscribers at a time when 1.3 billion analog lines were in use. ISDN has largely been replaced with digital subscriber line (DSL) systems of much higher performance. Prior to ISDN, the telephone system consisted of digital links like T1/ E1 on the long-distance lines between telephone company offices and analog signals on copper telephone wires to the customers, the " last mile". At the time, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
