Source : Free On-Line Dictionary of Computing
Primary Rate Interface
(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.
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).
(1995-01-18)