DPNSS was developed in the early 1980s by 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.

There are several kinds of access interfaces to ISDN defined as Basic Rate Interface ( BRI ), Primary Rate Interface ( PRI ) and Broadband ISDN ( B-ISDN ).

The other ISDN access available is the Primary Rate Interface ( PRI ), which is carried over an E1 ( 2048 kbit / s ) in most parts of the world.

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 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 Primary Rate Interface ( PRI ) is a standardized telecommunications service level within the Integrated Services Digital Network ( ISDN ) specification for carrying multiple DS0 voice and data transmissions between a network and a user.

The Integrated Services Digital Network ( ISDN ) prescribes two levels of service, the Basic Rate Interface ( BRI ), intended for the homes and small enterprises, and the Primary Rate Interface ( PRI ), for larger applications.

The Primary Rate Interface ( PRI ) consists of 23 64-kbit / s B-channels and one 64-kbit / s D-channel using a T1 line, often referred to as " 23B + D ", ( North American and Japanese standard ) or 30 B-channels and one D-channel using an E1 line ( Europe / rest of world ).

A T1 Primary Rate Interface user would have access to a 1. 472-Mbit / s data service.

An E1 Primary Rate Interface user would have access to a 1. 920 Mbit / s data service

The Primary Rate Interface channels are typically used by medium to large enterprises with digital PBXs to provide them digital access to the Public Switched Telephone Network ( PSTN ).

The Primary Rate user is hooked up directly to the telephone company central office.

fr: Primary Rate Interface

it: Primary Rate Interface

pl: Primary Rate Interface

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

In the typical telephony environment, a PBX connects to the local service provider through Primary Rate Interface ( PRI ) trunks.

Additionally, for voice T1s there are two main types: so-called " plain " or Inband T1s and PRI ( Primary Rate Interface ).

Non-Facility Associated Signalling or NFAS is a Primary Rate Interface configuration whereby multiple T1 carriers share a signalling channel ( or D channel ).

When a T1 circuit is used to carry Primary Rate ISDN one of the timeslots is used to carry the D channel.

A single Primary Rate ISDN circuit is thus sometimes described as 23B + D. There are 23 bearer channels carrying voice or data, and one D channel carrying the Common Channel Signaling.

Customers ordering a Primary Rate ISDN service will be charged for each signalling channel.

* Non-Facility Associated Signalling, a Primary Rate Interface configuration whereby multiple T1 carriers share a signaling channel ( or D channel ).

Primary research articles are published in the sister journals Proceedings of the Royal Society, Biology Letters, Journal of the Royal Society Interface, and Interface Focus.

Primary user input was decimal, via standard IBM 80 column punched cards and output was decimal, via a front panel display.

Primary pH standard values are determined using a concentration cell with transference, by measuring the potential difference between a hydrogen electrode and a standard electrode such as the silver chloride electrode.

Primary time standard –

He studied at the Arau Malay School until standard two, then from 5 January 1950 he continued his primary education at Wellesley Primary School in Penang followed by Westland Primary School until the end of 1955.

The town is the home of Ardwyn Nursery and Infants School, Oldford Nursery and Infants School, Gungrog Nursery and Infants School, Maes-y-dre Primary School and Welshpool High School is a secondary school which teaches a range of pupils from ages 11 – 18 and is consistently set to a very high standard of education throughout Key Stage 3 and 4 and A Level studies.

The OHMR maintains a military training academy to conduct state versions of standard Army professional development courses such as Basic Entry Level Training ( required for all non-prior service personnel ), Primary Leadership Development Course, Basic Noncommissioned Officer Course, and the Basic Officer Course.

Primary cells are made in a range of standard sizes to power small household appliances.

# Data Modeling — Primary process objects as well as protection and control functionality in the substation is modelled into different standard logical nodes which can be grouped under different logical devices.

* Primary rate access, a telecommunications standard