ISDN - 8 : BRI
This playlist provides an overview of #ISDN (Integrated Services Digital Network) development and operation.
• 35 : ISDN - Fundamentals of Communica...
There are two common ways to access an ISDN service. Let's first take a look at the BRI, or Basic Rate Interface. It is called basic rate because it is the lowest access rate, or speed.
A BRI service is normally used for small offices or residences. Both of these types of connections normally require only small data rates, so the BRI connection is sufficient.
A BRI service actually supplies 3 separate communication channels: 2 B channels and a D channel. The D channel is used for signaling, like dialing a phone number or sending a disconnect message. The two B channels are used to carry the communication streams.
These two B channels can be used separately or joined to form a higher bandwidth channel. This capability allows data, voice, and even video communication to use the connection at the same time. Separately, the B channels offer 64 kilobits per second of information. Together, they provide 128 kilobits of bandwidth.
For residential use, many customers use ISDN service to provide telephone and Internet service, and sometimes even cable television services.
When business offices use ISDN, the different channels are typically used for data and voice. Additionally, many corporations use ISDN service for videoconferencing services.