Integrated Services Digital Network (ISDN) is a circuit-switched telephone network system, designed to allow digital transmission of voice and data over ordinary telephone copper wires, resulting in better quality and higher data speeds than are available with analog "plain old telephone service" (POTS). More broadly, ISDN is a set of protocols for establishing and breaking circuit switched connections, and for advanced call features for the user. It was introduced in the late 1980's.^[1] In telecommunications, a circuit switching network is one that establishes a dedicated circuit (or channel) between nodes and terminals before the users may communicate. ... For other uses, see Telephone (disambiguation). ... For the scientific and engineering discipline studying computer networks, see Computer networking. ... A digital system is one that uses discrete values (often electrical voltages), especially those representable as binary numbers, or non-numeric symbols such as letters or icons, for input, processing, transmission, storage, or display, rather than a continuous spectrum of values (ie, as in an analog system). ... In telecommunications, transmission is the act of transmitting electrical messages (and the associated phenomena of radiant energy that passes through media). ... For other uses, see Data (disambiguation). ... The public switched telephone network (PSTN) is the concatenation of the worlds public circuit-switched telephone networks, in much the same way that the Internet is the concatenation of the worlds public IP-based packet-switched networks. ... Plain old telephone service, or POTS, are the services available from analogue telephones prior to the introduction of electronic telephone exchanges into the public switched telephone network. ... For other senses of this word, see protocol. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...

In a videoconference, ISDN provides simultaneous voice, video, and text transmission between individual desktop videoconferencing systems and group (room) videoconferencing systems. This article or section should be merged with Video teleconference A videoconference is a live connection between people in separate locations for the purpose of communication, usually involving audio and often text as well as video. ...

ISDN elements

The English term is a backronym that was thought to be better for English-language advertisements than the original, "Integriertes Sprach- und Datennetz" (German for "Integrated Speech and Data Net"). ^{[citation needed]} A backronym (or bacronym) is a phrase that is constructed after the fact from a previously existing abbreviation, the abbreviation being an initialism or an acronym. ...

• Integrated Services refers to ISDN's ability to deliver at minimum two simultaneous connections, in any combination of data, voice, video, and fax, over a single line. Multiple devices can be attached to the line, and used as needed. That means an ISDN line can take care of most people's complete communications needs at a much higher transmission rate, without forcing the purchase of multiple analog phone lines.

• Digital refers to its purely digital transmission, as opposed to the analog transmission of plain old telephone service (POTS). Use of an analog telephone modem for Internet access requires that the Internet service provider's (ISP) modem converts the digital content to analog signals before sending it and the user's modem then converts those signals back to digital when receiving. When connecting with ISDN there is no analog conversion. ISDN transmits data digitally, resulting in a very clear transmission quality. There is none of the static and noise of analog transmissions that can cause slow transmission speed.

• Network refers to the fact that ISDN is not simply a point-to-point solution like a leased line. ISDN networks extend from the local telephone exchange to the remote user and includes all of the telecommunications and switching equipment in between.

The purpose of the ISDN is to provide fully integrated digital services to the users. These services fall under three categories: bearer services, supplementary services and teleservices. In telecommunications, the local loop is the wiring between the central office (telephone exchange in British English) and the customers premises demarcation point. ... Plain old telephone service, or POTS, are the services available from analogue telephones prior to the introduction of electronic telephone exchanges into the public switched telephone network. ... A modem (from modulate and demodulate) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... “ISP” redirects here. ... A leased line is a symmetric telecommunications line connecting two locations together. ... A telephone operator manually connecting calls with patch cables at a telephone switchboard. ...

Consumer and industry perspectives

There are two points of view into the ISDN world. The most common viewpoint is that of the end user, who wants to get a digital connection into the telephone/data network from home, whose performance would be better than an ordinary analog modem connection. The typical end-user's connection to the Internet is related to this point of view, and discussion on the merits of various ISDN modems, carriers' offerings and tarriffing (features, pricing) are from this perspective. Much of the following discussion is from this point of view, but it should be noted that as a data connection service, ISDN has been mostly superseded by DSL. For other uses, see Telephone (disambiguation). ... A modem (from modulate and demodulate) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... A DSL Modem DSL or xDSL, is a family of technologies that provide digital data transmission over the wires of a local telephone network. ...

There is a second viewpoint: that of the telephone industry, where ISDN is a core technology. A telephone network can be thought of as a collection of wires strung between switching systems. The common electrical specification for the signals on these wires is T1 or E1. On a normal T1, the signalling is done with A&B bits to indicate on-hook or off-hook conditions and MF and DTMF tones to encode the destination number. ISDN is much better because messages can be sent much more quickly than by trying to encode numbers as long (100 ms per digit) tone sequences. This translated to much faster call setup times, which is greatly desired by carriers who have to pay for line time and also by callers who become impatient while their call hops from switch to switch. For the guitar distortion pedal, see BOSS DS-1. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... In Communications terms: A&B refers to a bit signaling procedure used in SF (D4) framed T1 transmission facilities where one bit from the sixth and twelfth frame of each of 24 T1 subchannels is used for carrying supervisory signaling. ... In telephony Multi-Frequency (MF) is an outdated, in-band signaling technique. ... This article does not cite any references or sources. ... The word tone is used in several different fields with different meanings. ... For other senses of the word code, see code (disambiguation). ... MS may refer to: Mississippi - a state in the United States of America Manuscript - a hand-written document (plural MSS). ...

It is also used as a smart-network technology intended to add new services to the public switched telephone network (PSTN) by giving users direct access to end-to-end circuit-switched digital services. The public switched telephone network (PSTN) is the network of the worlds public circuit-switched telephone networks, in much the same way that the Internet is the network of the worlds public IP-based packet-switched networks. ...

ISDN BRI (Basic Rate Interface) has never gained popularity as a telephone access technology in North America and today remains a niche product. However, most modern non-VoIP PBXs use PRI (Primary Rate Interface) T1 lines to communicate with a Telco Class 5 central office switch, replacing older analog two-way and Direct Inward Dialing (DID) trunks. PRI is capable of delivering Automatic Number Identification (ANI) in both directions so that the telephone number of an extension, rather than a company's main number, can be sent. It is still commonly used in recording studios, when a voice-over actor is in one studio, but the director and producer are in a studio at another location. ISDN is used because of its "guaranteed" real-time, not-over-the-Internet service, and its superior audio fidelity as compared to POTS service. A few companies make video conference call equipment that combine three BRI lines and six 64K channels to create a good quality picture. Basic rate interface (BRI, 2B+D, 2B1D) is an Integrated Services Digital Network configuration defined in the physical layer standard I.430 produced by the ITU. This configuration consists of two 64 kbit/s bearer channels (B channels) and one 16 kbit/s data channel (D channel). ... The primary rate interface (PRI) is a telecommunications standard for carrying multiple DS0 voice and data transmissions between two physical locations. ... Automatic number identification (ANI) is a feature of telephony intelligent network services that permits subscribers to display or capture the telephone numbers of calling parties. ... A recording studio is a facility for sound recording. ... Plain old telephone service, or POTS, are the services available from analogue telephones prior to the introduction of electronic telephone exchanges into the public switched telephone network. ...

In Japan, it became popular to some extent from around 1999 to 2001, but now that ADSL has been introduced, the number of subscribers is in decline. NTT, a dominant Japanese telephone company, provides an ISDN service with the names INS64 and INS1500, which are much less recognized than ISDN. Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional modem can provide. ... Nippon Telegraph and Telephone (日本電信電話 Nippon Denshin Denwa) is a telephone company that dominates the telecommunication market in Japan. ... A telephone company (or telco) provides telecommunications services such as telephony and data communications. ...

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 analogue 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. BT Group plc (formerly British Telecommunications plc) which trades as BT (pronounced Bee tee) (also previously as British Telecom and is still commonly known as such amongst the general public) is the privatised UK state telecommunications operator. ... Basic rate interface (BRI, 2B+D, 2B1D) is an Integrated Services Digital Network configuration defined in the physical layer standard I.430 produced by the ITU. This configuration consists of two 64 kbit/s bearer channels (B channels) and one 16 kbit/s data channel (D channel). ... The primary rate interface (PRI) is a telecommunications standard for carrying multiple DS0 voice and data transmissions between two physical locations. ... A USB Series “A” plug, the most common USB plug Universal Serial Bus (USB) is a serial bus standard to interface devices. ...

France Télécom offers ISDN services under their product name Numeris (2 B+D), of which a professional Duo and home Itoo version is available. ISDN is generally known as RNIS in France and has widespread availability. The introduction of ADSL is reducing ISDN use for data transfer and Internet access, although it is still common in more rural and outlying areas, and for applications such as business voice and point-of-sale terminals. France Télécom (Euronext: FTE, NYSE: FTE) (often spelled France Telecom, without the accents, in non-French text) is the main telecommunication company in France. ... A Private Branch eXchange (PBX) is a telephone exchange that serves a particular business or office, as opposed to one that a common carrier or telephone company operates for many businesses or for the general public. ... The BancNet (BN) Point-Of-Sale System is a local PIN-based electronic funds transfer (EFTPOS) payments solution operated by BancNet on behalf of the member banks and China UnionPay (CUP). ...

In Germany, ISDN is very popular with an installed base of 25 million channels (29% of all subscriber lines in Germany as of 2003 and 20% of all ISDN channels worldwide). Due to the success of ISDN, the number of installed analog lines is decreasing. Deutsche Telekom (DTAG) offers both BRI and PRI. Competing phone companies often offer ISDN only and no analog lines. Because of the widespread availability of ADSL services, ISDN is today primarily used for voice traffic, but is still very popular thanks to the pricing policy of German telcos. Today ISDN (BRI) and ADSL/VDSL are often bundled on the same line. [[Images:Bonn DTAG2. ... It has been suggested that VDSL2 be merged into this article or section. ...

In India, ISDN was very popular until the introduction of ADSL. Bharat Sanchar Nigam Limited, the largest communication service provider in India and a state owned company, is offering both ISDN BRI and PRI services across the country over its ISDN network. After the introduction of ADSL broadband technology with static IPs, the data transfer load is taken up by ADSL. But ISDN still plays a very big role as a backup network for point-to-point leased line customers and low cost reliable data network for organisations located all over India, such as Banks,E-seva centres, LIC, and so on. Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional modem can provide. ... Bharat Sanchar Nigam Limited (known as BSNL) is a public sector communications company in India. ...

Configurations

In ISDN, there are two types of channels, B (for "Bearer") and D (for "Delta"). B channels are used for data (which may include voice), and D channels are intended for signaling and control (but can also be used for data).

There are two ISDN implementations. Basic Rate Interface (BRI), also called Basic Rate Access (BRA) in Europe — consists of two B channels, each with bandwidth of 64 kbit/s, and one D channel with a bandwidth of 16 kbit/s. Together these three channels can be designated as 2B+D. Primary Rate Interface (PRI), also called Primary Rate Access (PRA) in Europe — contains a greater number of B channels and a D channel with a bandwidth of 64 kbit/s. The number of B channels for PRI varies according to the nation: in North America and Japan it is 23B+1D, with an aggregate bit rate of 1.544 Mbit/s (T1); in Europe, India and Australia it is 30B+1D, with an aggregate bit rate of 2.048 Mbit/s (E1). Broadband Integrated Services Digital Network (BISDN) is another ISDN implementation and it is able to manage different types of services at the same time. It is primarily used within network backbones and employs ATM. Basic rate interface (BRI, 2B+D, 2B1D) is an Integrated Services Digital Network configuration defined in the physical layer standard I.430 produced by the ITU. This configuration consists of two 64 kbit/s bearer channels (B channels) and one 16 kbit/s data channel (D channel). ... In telecommunications and computing, bit rate (sometimes written bitrate) is the frequency at which bits are passing a given (physical or metaphorical) point. It is quantified using the bit per second (bit/s) unit. ... The primary rate interface (PRI) is a telecommunications standard for carrying multiple DS0 voice and data transmissions between two physical locations. ... A megabit per second (mbps or mbit/s) is a unit of data transmission equal to 1,000 kilobits per second or 1,000,000 bits per second. ... For the guitar distortion pedal, see BOSS DS-1. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... In the 1980s the telecommunications industry conceived that digital services would follow much the same pattern as voice services, and conceived a grandiose vision of end-to-end circuit switched services, known as the Broadband Integrated Services Digital Network (B-ISDN). ... In the 1980s the telecommunications industry conceived that digital services would follow much the same pattern as voice services, and conceived a grandiose vision of end-to-end circuit switched services, known as the Broadband Integrated Services Digital Network (B-ISDN). ... A backbone network is the top level of a hierarchical computer network. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ...

Another alternative ISDN configuration can be used in which the B channels of an ISDN basic rate interface are bonded to provide a total duplex bandwidth of 128 kbit/s. This precludes use of the line for voice calls while the internet connection is in use. ISDN is also short for isosorbide dinitrate Integrated Services Digital Network (ISDN) is a type of circuit switched telephone network system, designed to allow digital (as opposed to analog) transmission of voice and data over ordinary telephone copper wires, resulting in better quality and higher speeds, than available with analog... Basic rate interface (BRI, 2B+D, 2B1D) is an Integrated Services Digital Network configuration defined in the physical layer standard I.430 produced by the ITU. This configuration consists of two 64 kbit/s bearer channels (B channels) and one 16 kbit/s data channel (D channel). ...

Using bipolar with eight-zero substitution encoding technique, call data is transmitted over the data (B) channels, with the signalling (D) channels used for call setup and management. Once a call is set up, there is a simple 64 kbit/s synchronous bidirectional data channel between the end parties, lasting until the call is terminated. There can be as many calls as there are bearer channels, to the same or different end-points. Bearer channels may also be multiplexed into what may be considered single, higher-bandwidth channels via a process called B channel bonding. B8ZS is an abbreviation for Bipolar with 8 Zeros Substitution (or Binary Eight Zero Substitution)- which is a method of line coding used in the T-carrier system which allows full 64 Kbits per second per channel, though it does not allow for Clear Channel Capability (CCC - 64 Kbits/sec. ... In telecommunications, multiplexing (also muxing or MUXing) is the combining of two or more information channels onto a common transmission medium using hardware called a multiplexer or (MUX). ...

The D channel can also be used for sending and receiving X.25 data packets, and connection to X.25 packet network, this is specified in X.31. In practice, X.31 was only commercially implemented in France and Japan. X.25 is an ITU-T standard protocol suite for wide area networks using leased lines, the phone or ISDN system as the networking hardware. ...

Reference points

A set of reference points are defined in the ISDN standard to refer to certain points between the telco and the end user ISDN equipment. A reference point is a location that is used in measurement of a huge variety of phenomena. ... Standards are produced by many organizations, some for internal usage only, others for use by a groups of people, groups of companies, or a subsection of an industry. ... A telephone company (or telco) provides telecommunications services such as telephony and data communications. ...

• R - defines the point between a non-ISDN device and a terminal adapter (TA) which provides translation to and from such a device
• S - defines the point between the ISDN equipment (or TA) and a Network Termination Type 2 (NT-2) device
• T - defines the point between the NT-2 and NT-1 devices¹
• U - defines the point between the NT-1 and the telco switch²

¹ Most NT-1 devices can perform the functions of the NT-2 as well, and so the S and T reference points are generally collapsed into the S/T reference point.
² Inside North America, the NT-1 device is considered customer premises equipment(CPE) and must be maintained by the customer, thus, the U interface is provided to the customer. In other locations, the NT-1 device is maintained by the telco, and the S/T interface is provided to the customer. In India, service providers provide U interface and an NT1 may be supplied by Service provider as part of service offering
R interface defines the point between a non-ISDN device and a terminal adapter (TA) which provides translation to and from such a device. ... In telecommunications, a terminal adapter is an interfacing device employed at the R reference point in an ISDN environment that allows a non-ISDN terminal at the physical layer to communicate with an ISDN network. ... S interface: For basic rate access in an Integrated Services Digital Network (ISDN) environment, a user-to-network interface reference point that (a) is characterized by a 4-wire, 144-kb/s (2B+D) user rate, (b) serves as a universal interface between ISDN terminals or terminal adapters and the... T-interface: For basic rate access in an Integrated Services Digital Network (ISDN) environment, a user-to-network interface reference point that (a) is characterized by a four-wire, 144-kb/s (2B+D) user rate, (b) accommodates the link access and transport layer function in the ISDN architecture, (c... Network termination 1 (NT1): In Integrated Services Digital Networks (ISDN), a functional grouping of customer-premises equipment that includes functions that may be regarded as belonging to OSI Layer 1, functions associated with ISDN electrical and physical terminations on the user premises. ... U interface: For basic-rate access in an Integrated Services Digital Network (ISDN) environment, a user-to-network interface reference point that is characterized by the use of a 2-wire-loop transmission system that (a) conveys information between the 4-wire user-to-network interface, the S/T reference... Customer premises (or provided) equipment (CPE): Terminal and associated equipment and inside wiring located at a subscribers premises and connected with a carriers communication channel(s) at the demarcation point (demarc) . In other words, CPE is an acronym meaning customer premises equipment. ...

Types of communications

Among the kinds of data that can be moved over the 64 kbit/s channels are pulse-code modulated voice calls, providing access to the traditional voice PSTN. This information can be passed between the network and the user end-point at call set-up time. In North America, ISDN is now used mostly as an alternative to analog connections, most commonly for Internet access. Some of the services envisioned as being delivered over ISDN are now delivered over the Internet instead. In Europe, and in Germany in particular, ISDN has been successfully marketed as a phone with features, as opposed to a POTS phone (Plain Old Telephone Service) with few or no features. Meanwhile, features that were first available with ISDN (such as Three-Way Call, Call Forwarding, Caller ID, etc.) are now commonly available for ordinary analog phones as well, eliminating this advantage of ISDN. Another advantage of ISDN was the possibility of multiple simultaneous calls (one call per B channel), e.g. for big families, but with the increased popularity and reduced prices of mobile telephony this has become less interesting as well, making ISDN unappealing to the private customer. However, ISDN is typically more reliable than POTS, and has a significantly faster call setup time compared with POTS, and IP connections over ISDN typically have some 30–35ms round trip time, as opposed to 120–180ms (both measured with otherwise unused lines) over 56k or V.34 modems, making ISDN more pleasant for telecommuters. Pulse-code modulation (PCM) is a modulation technique. ... The public switched telephone network (PSTN) is the concatenation of the worlds public circuit-switched telephone networks, in much the same way that the Internet is the concatenation of the worlds public IP-based packet-switched networks. ...

Where an analog connection requires a modem, an ISDN connection requires a terminal adapter (TA). The function of an ISDN terminal adapter is often delivered in the form of a PC card with an S/T interface, and single-chip solutions seem to exist, considering the plethora of combined ISDN- and ADSL-routers. A modem (from modulate and demodulate) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... In telecommunications, a terminal adapter is an interfacing device employed at the R reference point in an ISDN environment that allows a non-ISDN terminal at the physical layer to communicate with an ISDN network. ... Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional modem can provide. ... This article is about a computer networking device. ...

ISDN is commonly used in radio broadcasting. Since ISDN provides a high quality connection this assists in delivering good quality audio for transmission in radio. Most radio studios are equipped with ISDN lines as their main form of communication with other studios or standard phone lines. Radio broadcasting can be done via cable FM, local wire networks, satellite and the Internet. ...

Sample call

The following is an example of a Primary Rate (PRI) ISDN call showing the Q.921/LAPD and the Q.931/Network message intermixed (i.e. exactly what was exchanged on the D-channel). The call is originating from the switch where the trace was taken and goes out to some other switch, possibly an end-office LEC, who terminates the call. Link Access Procedures on the D channel (LAPD), specified in ITU-T Q.920 and ITU-T Q.921, is the second layer protocol on the ISDN protocol stack in the D channel. ... The ITU-T Recommendation Q.931 is ISDNs connection control protocol, roughly comparable to TCP in the Internet Protocol stack. ... Local exchange carrier is a regulatory term in telecommunications for so-called local telephone company. ...

The first line format is <time> <D-channel> <Transmitted/Received> <LAPD/ISDN message ID>. If the message is an ISDN level message, then a decoding of the message is attempted showing the various Information Elements that make up the message. All ISDN messages are tagged with an ID number relative to the switch that started the call (local/remote). Following this optional decoding is a dump of the bytes of the message in <offset> <hex> ... <hex> <ascii> ... <ascii> format.

The RR messages at the beginning prior to the call are the keep alive messages. Then you will see a SETUP message that starts the call. Each message is acknowledged by the other side with a RR.

 10:49:47.33 21/1/24 R RR 0000 02 01 01 a5 .... 10:49:47.34 21/1/24 T RR 0000 02 01 01 b9 .... 10:50:17.57 21/1/24 R RR 0000 02 01 01 a5 .... 10:50:17.58 21/1/24 T RR 0000 02 01 01 b9 .... 10:50:24.37 21/1/24 T SETUP Call Reference : 000062-local Bearer Capability : CCITT, Speech, Circuit mode, 64 kbit/s Channel ID : Implicit Interface ID implies current span, 21/1/5, Exclusive Calling Party Number : 8018023000 National number User-provided, not screened Presentation allowed Called Party Number : 3739120 Type: SUBSCRB 0000 00 01 a4 b8 08 02 00 3e 05 04 03 80 90 a2 18 03 .......>........ 0010 a9 83 85 6c 0c 21 80 38 30 31 38 30 32 33 30 30 ...l.!.801802300 0020 30 70 08 c1 33 37 33 39 31 32 30 0p..3739120 10:50:24.37 21/1/24 R RR 0000 00 01 01 a6 .... 10:50:24.77 21/1/24 R CALL PROCEEDING Call Reference : 000062-local Channel ID : Implicit Interface ID implies current span, 21/1/5, Exclusive 0000 02 01 b8 a6 08 02 80 3e 02 18 03 a9 83 85 .......>...... 10:50:24.77 21/1/24 T RR 0000 02 01 01 ba .... 10:50:25.02 21/1/24 R ALERTING Call Reference : 000062-local Progress Indicator : CCITT, Public network serving local user, In-band information or an appropriate pattern is now available 0000 02 01 ba a6 08 02 80 3e 01 1e 02 82 88 .......>..... 10:50:25.02 21/1/24 T RR 0000 02 01 01 bc .... 10:50:28.43 21/1/24 R CONNECT Call Reference : 000062-local 0000 02 01 bc a6 08 02 80 3e 07 .......>. 10:50:28.43 21/1/24 T RR 0000 02 01 01 be .... 10:50:28.43 21/1/24 T CONNECT_ACK Call Reference : 000062-local 0000 00 01 a6 be 08 02 00 3e 0f .......>. 10:50:28.44 21/1/24 R RR 0000 00 01 01 a8 .... 10:50:35.69 21/1/24 T DISCONNECT Call Reference : 000062-local Cause : 16, Normal call clearing. 0000 00 01 a8 be 08 02 00 3e 45 08 02 8a 90 .......>E.... 10:50:35.70 21/1/24 R RR 0000 00 01 01 aa .... 10:50:36.98 21/1/24 R RELEASE Call Reference : 000062-local 0000 02 01 be aa 08 02 80 3e 4d .......>M 10:50:36.98 21/1/24 T RR 0000 02 01 01 c0 .... 10:50:36.99 21/1/24 T RELEASE COMPLETE Call Reference : 000062-local 0000 00 01 aa c0 08 02 00 3e 5a .......>Z 10:50:36.00 21/1/24 R RR 0000 00 01 01 ac .... 10:51:06.10 21/1/24 R RR 0000 02 01 01 ad .... 10:51:06.10 21/1/24 T RR 0000 02 01 01 c1 .... 10:51:36.37 21/1/24 R RR 0000 02 01 01 ad .... 10:51:36.37 21/1/24 T RR 0000 02 01 01 c1 ....  

References

March is the third month of the year in the Gregorian Calendar and one of seven Gregorian months with the length of 31 days. ... Year 1986 (MCMLXXXVI) was a common year starting on Wednesday (link displays 1986 Gregorian calendar). ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 245th day of the year (246th in leap years) in the Gregorian calendar. ...

See also

Protocols

• DSS1 (ETSI "Euro-ISDN", also used in many non-European countries)
• DSS2 (Digital Subscriber Signalling System No. 2)
• ETS 300 specification at ETSI

• NI-1 (US National ISDN Phase 1)
• NI-2 (US National ISDN Phase 2)
• 4ESS (Lucent 4ESS specific protocol defined in AT&T TR 41459)

• INS-NET 64/1500 (Japanese national/NTT carrier-specific protocol)
• DACS used in the UK by British Telecom it uses non standard D channel signalling for Pair gain

• FTZ 1 TR 6 (obsolete German national protocol)
• TS.013/TS.014 (obsolete Australian national protocol)
• VN2/VN3/VN4 (obsolete French national protocols)

Specifications defining the physical layer and part of the data link layers of ISDN: Digital Subscriber System No. ... The European Telecommunications Standards Institute (ETSI) is a standardization organization of the telecommunications industry (equipment makers and network operators) in Europe, with worldwide projection. ... For other uses, see Europe (disambiguation). ... Digital Subscriber Signalling System No. ... Motto: (Out Of Many, One) (traditional) In God We Trust (1956 to date) Anthem: The Star-Spangled Banner Capital Washington D.C. Largest city New York City None at federal level (English de facto) Government Federal constitutional republic  - President George Walker Bush (R)  - Vice President Dick Cheney (R) Independence from... Motto: (Out Of Many, One) (traditional) In God We Trust (1956 to date) Anthem: The Star-Spangled Banner Capital Washington D.C. Largest city New York City None at federal level (English de facto) Government Federal constitutional republic  - President George Walker Bush (R)  - Vice President Dick Cheney (R) Independence from... In 1996, AT&T spun off its Systems and Technology units, along with the famous Bell Laboratories, to form a new company named Lucent Technologies (NYSE: LU). ... NTT may refer to Nippon Telegraph and Telephone The New Technology Telescope in La Silla, Chile. ... DACS is the name used by British Telecom (BT Group plc) in the United Kingdom for a 0+2 Pair gain system. ... BT Group plc (which trades as just BT, and is commonly known by its former name, British Telecom) is the privatised former British state telecommunications operator. ... A pair gain system is a transmission system that uses concentrators or multiplexers so that fewer wire pairs may be used than would otherwise be required to provide service to a given number of subscribers. ... FTZ 1 TR 6 (or 1 TR 6) is the standard for the obsolete German national digital singnalling protocol (D channel protocol) used for the ISDN. It has been superseded by DSS1 but is still in use on some lines and private exchanges. ...

• ISDN BRI: ITU-T I.430.
• ISDN PRI: ITU-T I.431.

From the point of view of the OSI architecture, an ISDN line has a stack of three protocols The ITU Telecommunication Standardization Sector (ITU-T) coordinates standards for telecommunications on behalf of the International Telecommunication Union (ITU) and is based in Geneva, Switzerland. ... The ITU Telecommunication Standardization Sector (ITU-T) coordinates standards for telecommunications on behalf of the International Telecommunication Union (ITU) and is based in Geneva, Switzerland. ...

• physical layer
• data link layer
• network layer (the ISDN protocol, properly) ^{[citation needed]}

Other

• ADSL
• ATM
• B-ISDN
• Internet
• H.320
• ETSI
• List of device bandwidths

Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... In the 1970s the telecommunications industry conceived that digital services would follow much the same pattern as voice services, and conceived a grandiose vision of end_to_end circuit switched services, known as the Broadband Integrated Services Digital Network (B-ISDN). ... H.320 is a umbrella recommendation by the ITU-T for running Multimedia (Audio/Video/Data) over ISDN based networks. ... The European Telecommunications Standards Institute (ETSI) is a standardization organization of the telecommunications industry (equipment makers and network operators) in Europe, with worldwide projection. ... This is a list of device bandwidths: the channel capacity (or, more informally, bandwidth) of some computer devices employing methods of data transport is listed by bit/s, kilobit/s (kbit/s), megabit/s (Mbit/s), or gigabit/s (Gbit/s) as appropriate and also MB/s or megabytes per...

External links

Wikibooks has a book on the topic of

Nets, Webs and the Information Infrastructure

• http://hea-www.harvard.edu/~fine/ISDN/
• http://www.itu.org
• http://www.ralphb.net/ISDN/
• http://www.isdnfree.com
• http://www.roblee.com/isdn.htm

Image File history File links Wikibooks-logo-en. ... Wikibooks logo Wikibooks, previously called Wikimedia Free Textbook Project and Wikimedia-Textbooks, is a wiki for the creation of books. ... Dial-up access is a form of Internet access through which the client uses a modem connected to a computer and a telephone line to dial into an Internet service providers (ISP) node to establish a modem-to-modem link, which is then routed to the Internet. ... A DSL Modem DSL or xDSL, is a family of technologies that provide digital data transmission over the wires of a local telephone network. ... Motorola Surfboard cable modem A cable modem is a type of modem that provides access to a data signal sent over the cable television infrastructure. ... // Fiber to the premises (FTTP) is a form of fiber-optic communication delivery in which an optical fiber is run directly onto the customers premises. ... Power-line internet is a new service still in its infancy that may eventually permit broadband Internet data to travel down standard high-voltage power lines. ... Official Wi-Fi logo Wi-Fi is a wireless technology brand owned by the Wi-Fi Alliance intended to improve the interoperability of wireless local area network products based on the IEEE 802. ... Bluetooth logo This article is about the electronic protocol named after Harald Bluetooth Gormson. ... WiBro (Wireless Broadband, Korean: 와이브로) is a wireless broadband Internet technology being developed by the Korean telecoms industry. ... WiMAX, the Worldwide Interoperability for Microwave Access, is a telecommunications technology aimed at providing wireless data over long distances in a variety of ways, from point-to-point links to full mobile cellular type access. ... UMTS-TDD is a mobile data network standard built upon the UMTS 3G cellular mobile phone standard, using a TD-CDMA, TD-SCDMA, or other 3GPP-approved, air interface that uses Time Division Duplexing to duplex spectrum between the up-link and down-link. ... High-Speed Packet Access (HSPA) is a collection of mobile telephony protocols that extend and improve the performance of existing UMTS protocols. ... Evolution-Data Optimized or Evolution-Data only, abbreviated as EV-DO or EVDO and often EV, is one telecommunications standard for the wireless transmission of data through radio signals, typically for broadband Internet access. ... Satellite Internet services are used in locations where terrestrial Internet access is not available and in locations which move frequently. ...