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DPNSS
The Digital Private Network Signalling System (DPNSS) is a network protocol used on digital trunk lines for connecting to PABX. It supports a defined set of inter-networking facilities. DPNSS was originally defined by British Telecom. The specification for the protocol is defined in BTNR188. The specification currently comes under the Network Interoperability Consultative Committee. History DPNSS was developed in the early 1980s by British Telecom (BT), or its forerunner, Post Office Telecommunications in recognition that the emerging Digital Private Circuit Primary Rate product 'Megastream' had to address the market for both data and voice, the latter being significantly greater because of the market for PBXs. At the time, BT dictated what signalling could be used on its leased lines and, whilst it only had a minority interest in the sales of PBXs, was requested by the PBX manufacturers to produce a standard to prevent the creation of a plethora of conflicting PBX protocols bei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Private Branch Exchange
A business telephone system is a telephone system typically used in business environments, encompassing the range of technology from the key telephone system (KTS) to the private branch exchange (PBX). A business telephone system differs from an installation of several telephones with multiple central office (CO) lines in that the CO lines used are directly controllable in key telephone systems from multiple telephone stations, and that such a system often provides additional features for call handling. Business telephone systems are often broadly classified into key telephone systems and private branch exchanges, but many combinations (hybrid telephone systems) exist. A key telephone system was originally distinguished from a private branch exchange in that it did not require an operator or attendant at a switchboard to establish connections between the central office trunks and stations, or between stations. Technologically, private branch exchanges share lineage with central ... [...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 tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DASS2
Digital Access Signalling System 2 (DASS2) is an obsolescent protocol defined by British Telecom (BT) for digital links to PSTN based on ISDN. Although still available on request, it has been superseded by ETS 300 102 ("EuroISDN"). DASS2 is an improved version over DASS1, based on experiences with DPNSS. In the UK, the ISDN concept was first introduced to customers by BT with their DASS2 connections. DASS2 (Digital Access Signalling System) is a BT-designed signalling standard, and was introduced before the Q.931 standard was finalised by the international community. British Telecom used the term ISDN when describing their DASS2 lines. DASS2 lines are provided to customers on a 2 Mbit/s link and can handle 30 simultaneous calls (64 kbit/s each). DASS2 is still offered by BT and other UK carriers. Q.931 is the name of the CCITT document that describes the agreed signalling format for International ISDN. CCITT had previously been known as ''International Telegraph and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiplexing
In telecommunications and computer networking, multiplexing (sometimes contracted to muxing) is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource—a physical transmission medium. For example, in telecommunications, several telephone calls may be carried using one wire. Multiplexing originated in telegraphy in the 1870s, and is now widely applied in communications. In telephony, George Owen Squier is credited with the development of telephone carrier multiplexing in 1910. The multiplexed signal is transmitted over a communication channel such as a cable. The multiplexing divides the capacity of the communication channel into several logical channels, one for each message signal or data stream to be transferred. A reverse process, known as demultiplexing, extracts the original channels on the receiver end. A device that performs the multiplexing is called a multiplexer (MUX), and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BT Group
BT Group plc (formerly British Telecom) is a British Multinational corporation, multinational telecommunications holding company headquartered in London, England. It has operations in around 180 countries and is the largest provider of fixed-line, Internet access, broadband and Mobile telephony, mobile services in the UK, and also provides subscription television and Information technology, IT services. BT's origins date back to the founding in 1846 of the Electric Telegraph Company, the world's first public telegraph company, which developed a nationwide communications network. BT Group as it came to be started in 1912, when the General Post Office, a government department, took over the system of the National Telephone Company becoming the monopoly telecoms supplier in the United Kingdom. The Post Office Act of 1969 led to the GPO becoming a public corporation, Post Office Telecommunications. The ''British Telecom'' brand was introduced in 1980, and became independent of the R ... [...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, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DASS1
Digital Access Signalling System 1 (DASS1) is a proprietary protocol defined by British Telecom to provide ISDN services in the United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan .... It is now obsolete, having been replaced by DASS2. This too will become obsolete over the coming years as Q.931, a European standard, becomes widely adopted in the EU. References BT Group History of telecommunications in the United Kingdom Integrated Services Digital Network {{telecomm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siemens
Siemens AG ( ) is a German multinational technology conglomerate. It is focused on industrial automation, building automation, rail transport and health technology. Siemens is the largest engineering company in Europe, and holds the position of global market leader in industrial automation and industrial software. The origins of the conglomerate can be traced back to 1847 to the ''Telegraphen Bau-Anstalt von Siemens & Halske'' established in Berlin by Werner von Siemens and Johann Georg Halske. In 1966, the present-day corporation emerged from the merger of three companies: Siemens & Halske, Siemens-Schuckert, and Siemens-Reiniger-Werke. Today headquartered in Munich and Berlin, Siemens and its subsidiaries employ approximately 320,000 people worldwide and reported a global revenue of around €78 billion in 2023. The company is a component of the DAX and Euro Stoxx 50 stock market indices. As of December 2023, Siemens is the second largest German company by market ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nortel
Nortel Networks Corporation (Nortel), formerly Northern Telecom Limited, was a Canadian Multinational corporation, multinational telecommunications and data networking equipment manufacturer headquartered in Ottawa, Ontario. It was founded in Montreal, Quebec in 1895 as the Northern Electric and Manufacturing Company, or simply Northern Electric. Until an antitrust settlement in 1949, Northern Electric was owned mostly by Bell Canada and the Western Electric, Western Electric Company of the Bell System, producing large volumes of telecommunications equipment based on licensed Western Electric designs. At its height, Nortel accounted for more than a third of the total valuation of all companies listed on the Toronto Stock Exchange (TSX), employing 94,500 people worldwide. In 2009, Nortel filed for bankruptcy protection in Canada and the United States, triggering a 79% decline in its corporate stock price. The bankruptcy case was the List of corporate collapses and scandals, larg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voice VPN
A VoIP VPN combines voice over IP and virtual private network technologies to offer a method for delivering secure voice. Because VoIP transmits digitized voice as a stream of data, the VoIP VPN solution accomplishes voice encryption quite simply, applying standard data-encryption mechanisms inherently available in the collection of protocols used to implement a VPN. The VoIP gateway-router first converts the analog voice signal to digital form, encapsulates the digitized voice within IP packets, then encrypts the digitized voice using IPsec, and finally routes the encrypted voice packets securely through a VPN tunnel. At the remote site, another VoIP router decodes the voice and converts the digital voice to an analog signal for delivery to the phone. A VoIP VPN can also run within an IP in IP tunnel or using SSL-based OpenVPN. There is no encryption in former case, but traffic overhead is significantly lower in comparison with IPsec tunnel. The advantage of OpenVPN tunneling i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VoIP
Voice over Internet Protocol (VoIP), also known as IP telephony, is a set of technologies used primarily for voice communication sessions over Internet Protocol (IP) networks, such as the Internet. VoIP enables voice calls to be transmitted as data packets, facilitating various methods of voice communication, including traditional applications like Skype, Microsoft Teams, Google Voice, and VoIP phones. Regular telephones can also be used for VoIP by connecting them to the Internet via analog telephone adapters (ATAs), which convert traditional telephone signals into digital data packets that can be transmitted over IP networks. The broader terms Internet telephony, broadband telephony, and broadband phone service specifically refer to the delivery of voice and other communication services, such as fax, SMS, and voice messaging, over the Internet, in contrast to the traditional public switched telephone network (PSTN), commonly known as plain old telephone service (POTS) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
H323
H.323 is a recommendation from the ITU-T, ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network. The H.323 standard addresses call signaling and control, multimedia transport and control, and bandwidth control for point-to-point and multi-point conferences. It is widely implemented by voice and videoconferencing equipment manufacturers, is used within various Internet real-time applications such as GnuGK and NetMeeting and is widely deployed worldwide by service providers and enterprises for both voice and video services over Internet Protocol, IP networks. It is a part of the ITU-T H.32x series of protocols, which also address multimedia communications over Integrated Services Digital Network, ISDN, the public switched telephone network, PSTN or Signaling System 7, SS7, and 3G mobile networks. H.323 call signaling is based on the ITU-T Recommendation Q.931 protocol and is suited for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
