Editing Basic Rate Interface (section)

{{Short description|ISDN configuration}}
{{more footnotes|date=March 2013}}

[[File:ISDN telefono.jpg|thumb|right|An ISDN phone]]

'''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 line]]s similar to those that have long been used for [[Plain old telephone service|voice-grade telephone service]].
As such, an ISDN BRI connection can use the [[Plain old telephone service|existing telephone infrastructure]] at a business.

The BRI configuration provides 2 data (bearer) channels ([[B channel]]s) at 64&nbsp;kbit/s each and 1 control (delta) channel ([[D channel]]) at 16&nbsp;kbit/s. The B channels are used for [[Human voice|voice]] or user [[data]], and the D channel is used for any combination of data, [[Signaling (telecommunications)|control signaling]], and [[X.25]] packet networking.<ref>{{foldoc|Basic+Rate+Interface}}</ref> The 2 [[B channel]]s can be aggregated by [[channel bonding]] providing a total data rate of 128&nbsp;kbit/s. The BRI ISDN service is commonly installed for [[residential]] or small business service (ISDN [[PABX]]) in many countries.

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