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ADSL (Asymmetric Digital Subscriber Line)

ADSL (Asymmetric Digital Subscriber Line) is a technology for transmitting digital information at a high bandwidth on existing phone lines to homes and businesses. Unlike regular dialup phone service, ADSL provides continuously-available, "always on" connection. ADSL is asymmetric in that it uses most of the channel to transmit downstream to the user and only a small part to receive information from the user. ADSL simultaneously accommodates analogue (voice) information on the same line. ADSL is generally offered at downstream data rates from 512 Kbps to about 6 Mbps. A form of ADSL, known as Universal ADSL or G.lite, has been approved as a standard by the ITU-TS.

ADSL was specifically designed to exploit the one-way nature of most multimedia communication in which large amounts of information flow toward the user and only a small amount of interactive control information is returned. Several experiments with ADSL to real users began in 1996. In 1998, wide-scale installations began in several parts of the U.S. In 2000 and beyond, ADSL and other forms of DSL are expected to become generally available in urban areas. With ADSL (and other forms of DSL), telephone companies are competing with cable companies and their cable modem services.

Basic Rate Interface (BRI)

Basic Rate Interface (BRI) is an ITU-T ISDN multipurpose user interface standard for simultaneous voice and data services provided over two 64-kb/s bearer channels and one 16-kb/s data channel (2B+D) access arrangement to each user location. The B channels are used for voice or user data, and the D channel is used for any combination of: data, control/signalling and X.25 packet networking. The two B channels can be bonded together giving a total data rate of 128 kbit/s. BRI is the kind of ISDN interface most likely to be found in residential service.

CTI Computer Telephony Integration

CTI Computer Telephony Integration allows a PABX system handset to send and receive data fro a PC. This allows a pc to see the phone number of an incoming call, it will then look for the number in your software and pop the record associated with the phone number. The system uses Microsoft CAPI & TAPI protocols.

Direct Dial Index (DDI)

Direct Dialing In (DDI), also known as Direct Inward Dialing (DID), is the ability or service feature for a caller outside a company to call an internal extension without having to pass through an operator or attendant. In large PBX systems, the dialed digits are passed down the line from the CO (central office). The PBX then completes the call. Direct Inward Dialing is often proposed as Centrex's major feature. But automated attendants (a specialized form of interactive voice response systems) also provide a similar service. Direct Dial Index (DDI) numbers are numbers associated to ISDN telephone lines. Analogue lines are associated with one phone number, an ISDN line can carry upto a 100 DDI numbers.

Integrated Services Digital Network or Isolated Subscriber Digital Network (ISDN,

Integrated Services Digital Network or Isolated Subscriber Digital Network (ISDN), originally "Integriertes Sprach- und Datennetz" (German for "Integrated Speech and Data Network"), is a telephone system network. Prior to the ISDN, the phone system was viewed as a way to transport voice, with some special services available for data. The key feature of the ISDN is that it integrates speech and data on the same lines, adding features that were not available in the classic telephone system. There are several kinds of access interfaces to the ISDN defined: Basic Rate Interface (BRI), Primary Rate Interface (PRI) and Broadband-ISDN (B-ISDN).

In the UK, British Telecom (BT) provides ISDN2e (BRI) as well as ISDN30 (PRI). Until April 2006, they also offered Home Highway and Business Highway, which are BRI ISDN-based services that offer integrated analog connectivity as well as ISDN. Later versions of the Highway products also included built-in USB sockets for direct computer access. Home Highway has been bought by many home users, usually for Internet connection, although not as fast as ADSL, because it was available before ADSL and in places where ADSL does not reach. Virgin Media also use ISDN lines for customers of Virgin Broadband who live in cable TV areas.



MSN Naming


Multiple Subscriber Number (MSN) is an incoming call routing method in which a group of phone numbers is assigned to a particular PRI ISDN line by the telephone company. A PRI ISDN line is usually assigned multiple numbers in the US and in Europe. If you use ISDN lines a name can be assigned to each Direct Dial Index number so that when a call comes in on company A's phone number the system handset will display Company A so that the call be answered accordingly, and vice versa for any other DDI numbers.

POTS (Plain Old Telephone Service)

Plain Old Telephone Service (POTS) is the standard, analogue telephone service which remains the basic form of residential and small business telephone service nearly everywhere in the world. Plain Old Telephone Service was originally known as the Post Office Telephone Service in many countries. It has been available almost since the introduction of the telephone system in the late 19th century, mostly unchanged to the normal user since then despite the introduction of electronic telephone exchanges into the public switched telephone network since the middle of the 20th century. POTS is a term sometimes used in discussion of new telephone technologies in which the question of whether and how existing voice transmission for ordinary phone communication can be accommodated. For example, Asymmetric Digital Subscriber Line and Integrated Services Digital Network connections provide some part of their channels for "plain old telephone service" while providing most of their bandwidth for digital data transmission.

Primary Rate Interface (PRI)

Primary Rate Interface (PRI) is an ISDN interface for primary rate access, which consists of a single 64-kbps D channel plus 23 (T1) or 30 (E1) B channels for voice or data. PRI intended for larger users, such as business users. The other ISDN interface is the Basic Rate Interface (BRI), which is for homes and small businesses.

Session Initiation Protocol (SIP)

Session Initiation Protocol (SIP) is the IETF's standard for establishing VOIP connections. SIP is an application layer control protocol for creating, modifying and terminating sessions with one or more participants. The architecture of SIP is similar to that of HTTP (client-server protocol). Requests are generated by the client and sent to the server. The server processes the requests and then sends a response to the client. A request and the responses for that request make a transaction.
Telephony Application Programming Interface (TAPI) The Telephony Application Programming Interface (TAPI) is an API developed by Microsoft and Intel, which enables PCs running Microsoft Windows to use telephone services.

Voice over IP (VOIP)

Voice over IP (VOIP) uses the Internet Protocol (IP) to transmit voice as packets over an IP network. Using VOIP protocols, voice communications can be achieved on any IP network regardless it is Internet, Intranets or Local Area Networks (LAN). In a VOIP enabled network, the voice signal is digitized, compressed and converted to IP packets and then transmitted over the IP network. VOIP signaling protocols are used to set up and tear down calls, carry information required to locate users and negotiate capabilities. The key benefits of Internet telephony (voice over IP) are the very low cost, the integration of data, voice and video on one network, the new services created on the converged network and simplified management of end user and terminals.
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Quickstream Ltd T/A Digital Office Solutions, Registered in England Registration Number 04193475 Vat Registration Number 858 1773 84 Director J M Waters
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