Basic Rate Interface

BRI2B1DBasic Rate (BRI)basic rate accessBasic Rate ISDNBRA or BRIISDN BRIISDN2
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.wikipedia
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Integrated Services Digital Network

ISDN ISDNISDN30
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.
The ISDN standards define several kinds of access interfaces, such as Basic Rate Interface (BRI), Primary Rate Interface (PRI), Narrowband ISDN (N-ISDN), and Broadband ISDN (B-ISDN).

B channel

B-Channelbearer (B) channelsbearer channel
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. In contrast to the BRI, the Primary Rate Interface (PRI) configuration provides more B channels and operates at a higher bit rate. The 2 B channels can be aggregated by channel bonding providing a total data rate of 128 kbit/s.
The term is applied primarily in relation to the ISDN access interfaces (PRA or PRI and BRA or BRI), since deeper in the PSTN network an ISDN bearer channel is essentially indistinguishable from any other bearer channel.

D channel

data (D) channel
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 bit rate of the D channel of a basic rate interface is 16 kbit/s, whereas it amounts to 64 kbit/s on a primary rate interface.

X.25

X25CCITT X.25 recommendationISO/IEC 8208
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.
In some countries, like the Netherlands or Germany, it is possible to use a stripped version of X.25 via the D-channel of an ISDN-2 (or ISDN BRI) connection for low-volume applications such as point-of-sale terminals; but, the future of this service in the Netherlands is uncertain.

T interface

T
The in-house part is defined in I.430 produced by the International Telecommunication Union (ITU). The S/T Interface (S 0 ) 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 . The S 0 offers point-to-point or point-to-multipoint operation; Max length: 900m (point-to-point), 300m (point-to-multipoint).
A T-interface or T reference point is used for basic rate access in an Integrated Services Digital Network (ISDN) environment.

Bit rate

bitratedata ratedata transfer rate
The in-house part is defined in I.430 produced by the International Telecommunication Union (ITU). The S/T Interface (S 0 ) 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 . The S 0 offers point-to-point or point-to-multipoint operation; Max length: 900m (point-to-point), 300m (point-to-multipoint). In contrast to the BRI, the Primary Rate Interface (PRI) configuration provides more B channels and operates at a higher bit rate.
The net bit rate of ISDN2 Basic Rate Interface (2 B-channels + 1 D-channel) of 64+64+16 = 144 kbit/s also refers to the payload data rates, while the D channel signalling rate is 16 kbit/s.

Business telephone system

PBXprivate branch exchangekey telephone system
The BRI ISDN service is commonly installed for residential or small business service (ISDN PABX) in many countries.
Using small PBXs for ISDN is a logical step, since the ISDN basic rate interface provides two logical phone lines (via two ISDN B channels) which can be used in parallel.

Primary Rate Interface

PRIprimary ratePRA or PRI
In contrast to the BRI, the Primary Rate Interface (PRI) configuration provides more B channels and operates at a higher bit rate.
Basic Rate Interface (BRI): two 64-kbit/s B channels and one 16-kbit/s D channel, intended for small enterprises and residential service.

U interface

UU k0 U K0 -Interface
The U p 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 of the applicable cable length, two varieties are implemented, U pN and U p0 . The U k0 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 km.
The U interface or U reference point is a Basic Rate Interface (BRI) in the local loop of an Integrated Services Digital Network (ISDN).

I.430

The in-house part is defined in I.430 produced by the International Telecommunication Union (ITU). The S/T Interface (S 0 ) 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 . The S 0 offers point-to-point or point-to-multipoint operation; Max length: 900m (point-to-point), 300m (point-to-multipoint).
The I.431 standard is known as the 'PRI Physical Layer' whereas the I.430 is known as the 'BRI Physical Layer'.

Network termination 1

NT1network termination type 1network terminator
The U p 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 of the applicable cable length, two varieties are implemented, U pN and U p0 . The U k0 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 km.
In a Basic Rate Interface, the NT1 connects to line termination (LT) equipment in the provider's telephone exchange via the local loop two wire U interface and to customer equipment via the four wire S interface or T interface.

Local loop

subscriber lineloopsubscriber loop
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.

Plain old telephone service

POTSLocal Telephone Servicetelephone
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.

Human voice

Vocalsvocalvoice
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.

Data

statistical datascientific datadatum
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.

Signaling (telecommunications)

signalsignalingsignalling
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.

Link aggregation

channel bondingLACP802.3ad
The 2 B channels can be aggregated by channel bonding providing a total data rate of 128 kbit/s.

Residential area

residentialresidential developmentresidential building
The BRI ISDN service is commonly installed for residential or small business service (ISDN PABX) in many countries.

International Telecommunication Union

ITUInternational Telecommunication Union´sInternational Telecommunications Union
The in-house part is defined in I.430 produced by the International Telecommunication Union (ITU). The S/T Interface (S 0 ) 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 . The S 0 offers point-to-point or point-to-multipoint operation; Max length: 900m (point-to-point), 300m (point-to-multipoint).

Telecommunications link

uplinkdownlinkforward link
The in-house part is defined in I.430 produced by the International Telecommunication Union (ITU). The S/T Interface (S 0 ) 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 . The S 0 offers point-to-point or point-to-multipoint operation; Max length: 900m (point-to-point), 300m (point-to-multipoint).

Network packet

packetpacketsdata packet
The in-house part is defined in I.430 produced by the International Telecommunication Union (ITU). The S/T Interface (S 0 ) 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 . The S 0 offers point-to-point or point-to-multipoint operation; Max length: 900m (point-to-point), 300m (point-to-multipoint).

Bit

binary digitbitsbinary digits
The in-house part is defined in I.430 produced by the International Telecommunication Union (ITU). The S/T Interface (S 0 ) 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 . The S 0 offers point-to-point or point-to-multipoint operation; Max length: 900m (point-to-point), 300m (point-to-multipoint).

Synchronization

synchronoussynchronizedsynchronize
The in-house part is defined in I.430 produced by the International Telecommunication Union (ITU). The S/T Interface (S 0 ) 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 . The S 0 offers point-to-point or point-to-multipoint operation; Max length: 900m (point-to-point), 300m (point-to-multipoint).

Up0-interface

U p0 U p0 -interface
The U p 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 of the applicable cable length, two varieties are implemented, U pN and U p0 . The U k0 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 km.

Echo suppression and cancellation

echo cancellationecho cancellerecho suppressor
The U p 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 of the applicable cable length, two varieties are implemented, U pN and U p0 . The U k0 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 km.