Skip to content
Main menu
  • Main page
  • Discover
  • Unexpected connections
  • Topics
  • Random article
  • Search
Your library
  • Saved articles
  • Recent discoveries
  • Rabbit-hole trails
Topic areas
  • Computer Science
  • Mathematics
  • Physics
  • Engineering
  • Biology
  • Economics
  • Curiosities
WikiholeDeeper into Wikipedia
EnglishEN
  • Saved
  • History

  • Article text and media come live from Wikipedia via the official MediaWiki API and are available under the Creative Commons Attribution-ShareAlike 4.0 License; additional terms may apply. Each article links to its source and revision.
  • WikiHole is an independent project and is not affiliated with the Wikimedia Foundation.
  • How ranking works
  • All topics
  • Reading history
  • Random article
  • MediaWiki API

Basic Rate Interface

  • Article
  • Rabbit hole
  • Read
  • View history
Tools
Actions
  • Read
  • View history
General
  • Recent changes
  • Related articles
  • Random discovery
This article
Reading time
1 min
Topic
Computer Science
Quality
Start-class
Views
80 in 14 days
Last edited
2 May 2026
Print/export
  • Printable version
In other projects
  • Wikidata item
From Wikipedia, the free encyclopedia
Rabbit hole:
  1. Basic Rate Interface
Basic Rate Interface
ISDN configuration

Basic Rate Interface (BRI, 2B+D, 2B1D) or Basic Rate Access is an Integrated Services Digital Network (ISDN) configuration intended primarily for use in subscriber lines similar to those that have long been used for voice-grade telephone service. As such, an ISDN BRI connection can use the existing telephone infrastructure at a business.

The BRI configuration provides 2 data (bearer) channels (B channels) at 64 kbit/s each and 1 control (delta) channel (D channel) at 16 kbit/s. The B channels are used for voice or user data, and the D channel is used for any combination of data, control signaling, and X.25 packet networking.1 The 2 B channels can be aggregated by channel bonding providing a total data rate of 128 kbit/s. The BRI ISDN service is commonly installed for or small business service (ISDN ) in many countries.

residential
PABX

In contrast to the BRI, the Primary Rate Interface (PRI) configuration provides more B channels and operates at a higher bit rate.

Loading the rest of the article…

Recent changes

Rabbit hole

Where Basic Rate Interface leads. Every connection below has a source: a link in this article, a shared Wikipedia category, or CirrusSearch text similarity. Articles already on your trail are left out.

Contents
  • (Top)
  • Physical interfaces
  • References
  • External links
  • Recent changes
  • Rabbit hole
Contents
Contents5 sections
  • (Top)
  • Physical interfaces
  • References
  • External links
  • Recent changes
  • Rabbit hole

Physical interfaces

The BRI is split in two sections: a) in-house cabling (S/T reference point or S-bus) from the ISDN terminal up to the network termination 1 (NT1) and b) transmission from the NT1 to the central office (U reference point).

  • The in-house part is defined in I.430 produced by the International Telecommunication Union (ITU). The S/T-interface (S0) uses four wires; one pair for the uplink and another pair for the downlink. It offers a full-duplex mode of operation. The I.430 protocol defines 48-bit packets comprising 16 bits from the B1 channel, 16 bits from B2 channel, 4 bits from the D channel, and 12 bits used for synchronization purposes. These packets are sent at a rate of 4 kHz, resulting in a gross bit rate of 192 kbit/s and – giving the data rates listed above – a maximum possible throughput of 144kbit/s. The S0 offers point-to-point or point-to-multipoint operation; Max length: 900 metres (3,000 ft) (point-to-point), 300 metres (980 ft) (point-to-multipoint).
  • The Up Interface uses two wires. The gross bit rate is 160 kbit/s; 144 kbit/s throughput, 12 kbit/s sync and 4 kbit/s maintenance. The signals on the U reference point are encoded by two modulation techniques: 2B1Q in North America, Italy and Switzerland, and 4B3T elsewhere. Depending on the applicable cable length, two varieties are implemented, UpN and Up0. The Uk0 interface uses one wire pair with echo cancellation for the long last mile cable between the telephone exchange and the network terminator. The maximum length of this BRI section is between 4 and 8 kilometres (2.5 and 5.0 mi).

References

  1. 1This article is based on material taken from Basic+Rate+Interface at the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.

External links

  • "BRI defined on birds-eye.net". Archived from the original on 2012-08-25. Retrieved 2012-08-25.
Study aids for Basic Rate Interface

Terminology

BRI
Basic Rate Interface (BRI, 2B+D, 2B1D) or Basic Rate Access is an Integrated Services Digital Network (ISDN) configuration intended primarily for use in subscriber lines similar to those that have long been used for voice-grade telephone service.
2B+D
Basic Rate Interface (BRI, 2B+D, 2B1D) or Basic Rate Access is an Integrated Services Digital Network (ISDN) configuration intended primarily for use in subscriber lines similar to those that have long been used for voice-grade telephone service.
2B1D
Basic Rate Interface (BRI, 2B+D, 2B1D) or Basic Rate Access is an Integrated Services Digital Network (ISDN) configuration intended primarily for use in subscriber lines similar to those that have long been used for voice-grade telephone service.
Basic Rate Access
Basic Rate Interface (BRI, 2B+D, 2B1D) or Basic Rate Access is an Integrated Services Digital Network (ISDN) configuration intended primarily for use in subscriber lines similar to those that have long been used for voice-grade telephone service.

Terms the article defines in bold, quoted in context.

Categories:
  • Integrated Services Digital Network

422 words · 1 references · revision 1352161142 · CC BY-SA 4.0

General
  • Recent changes
  • Related articles
  • Random discovery
This article
Reading time
1 min
Topic
Computer Science
Quality
Start-class
Views
80 in 14 days
Last edited
2 May 2026

Key concepts

  • B channel3
  • Plain old telephone service2
  • Bit rate2
  • Integrated Services Digital Network1
  • Subscriber line1
  • D channel1
  • Human voice1
  • Data1
  • Signaling (telecommunications)1
  • X.251

The articles this one links to most, weighted towards the introduction.

Print/export
  • Printable version
In other projects
  • Wikidata item
Created
25 Jul 2002
History
182 edits
113 contributors
No edits in the last 30 days
Last edited
2 May 2026

182 revisions in total · 113 contributors

  1. 2 May 2026, 13:06 UTCCtillmadd hyperlinks to existing articles+8diff
  2. 19 Nov 2024, 18:47 UTCKvngfoldoc attribution, see Template_talk:FOLDOC#It_doesn't_matter_whether_readers_care+70diff
  3. 4 Sept 2024, 20:28 UTCKvngmavoid unnec redirect. MOS:SLASH.+3diff
  4. 23 Jun 2024, 21:13 UTCStephan Leeds§ Physical interfaces “ - ” × 2+10diff
  5. 25 Apr 2024, 23:34 UTCCoolieCoolstermAdded non-breaking space to non-template file size, frequency, bitrate, and bandwidth values (via WP:JWB)+35diff
  6. 9 Dec 2023, 13:35 UTCAnonymous contributor§ Physical interfaces+33diff
  7. 6 Nov 2022, 03:31 UTCMeno25empty section−28diff
  8. 15 Dec 2021, 03:04 UTCParadoctormDisambiguating links to Last mile (link changed to Last mile (telecommunications)) using DisamAssist.+31diff

View full revision history

Created
25 Jul 2002
History
182 edits
113 contributors
No edits in the last 30 days
Last edited
2 May 2026

Go deeper: linked from this article

  • Linked from the introduction

    ISDN

    Set of digital telephony standards

    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.

    20 min readGo deeper

  • Linked from the introduction

    X.25

    Standard protocol suite for packet switched wide area network (WAN) communication

    X.25 is an ITU-T standard protocol suite for packet-switched data communication in wide area networks (WAN).

    15 min readGo deeper

  • Linked from the introduction

    Bit rate

    Information transmission rate expressed in bits per second

    In telecommunications and computing, bit rate (bitrate or as a variable R) is the number of bits that are conveyed or processed per unit of time.

    12 min readGo deeper

  • Linked from the introduction

    Link aggregation

    Using multiple network connections in parallel to increase capacity and reliability

    In computer networking, link aggregation is the combining (aggregating) of multiple network connections in parallel by any of several methods.

    13 min readGo deeper

  • Linked from the introduction

    Business telephone system

    Telephone system typically used in business environments

    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).

    11 min readGo deeper

  • Linked from the introduction

    Local loop

    In telephony, the last part of the connection to the customer

    In telephony, the local loop (also referred to as the local tail, subscriber line, or in the aggregate as the last mile) is the physical link or circuit that connects from the demarcation point of…

    1 min readGo deeper

  • Linked from the introduction

    Human voice

    Sound made by a human being using the vocal tract

    The human voice consists of sound made by a human being using the vocal tract, including talking, singing, laughing, crying, screaming, shouting, humming or yelling.

    9 min readGo deeper

  • Linked from the introduction

    Data

    Unit of information

    Data (DAY-tə, US also DAT-ə) is a collection of discrete or continuous values that conveys information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted formally.

    10 min readGo deeper

  • Linked from the introduction

    Residential area

    Land use in which housing predominates, as opposed to industrial and commercial areas

    A residential area is a land used in which housing predominates, as opposed to industrial and commercial areas. Housing may vary significantly between, and through, residential areas.

    4 min readGo deeper

Adjacent: shared categories and similar text

  • Linked in “Physical interfaces”

    Telephone exchange

    Telecommunication system for establishing telephone calls

    A telephone exchange, telephone switch, or central office is a central component of a telecommunications system in the public switched telephone network (PSTN) or in large enterprises.

    17 min readGo deeper

  • Linked in “Physical interfaces”

    Echo suppression and cancellation

    Preventing or removing echo in telephony

    Echo suppression and echo cancellation are methods used in telephony to improve voice quality by preventing echo from being created or removing it after it is already present.

    7 min readGo deeper

  • Linked in “Physical interfaces”

    Hertz

    SI unit of frequency

    The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second.

    6 min readGo deeper

  • Linked in “Physical interfaces”

    Telecommunications link

    Communication channel between two or more devices

    In a telecommunications network, a link is a communication channel that connects two or more devices for the purpose of data transmission.

    2 min readGo deeper

  • Linked in “Physical interfaces”

    International Telecommunication Union

    Specialized agency of the United Nations

    The International Telecommunication Union (ITU) is a specialized agency of the United Nations responsible for many matters related to information and communication technologies.

    17 min readGo deeper