([PRI]) A type of [ISDN] connection. In North America and Japan, this consists of 24 channels, usually divided into 23 B channels and 1 D channel, and runs over the same physical interface as [T1]. Elsewhere the [PRI] has 31 user channels, usually divided into 30 B channels and 1 D channel and is based on the [E1] interface.
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[PRI] is typically used for connections such as one between a PBX (private branch exchange, a telephone exchange operated by the customer of a telephone company) and a CO (central office, of the telephone company) or IXC (inter exchange carrier, a long distance telephone company).
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