(PRI) A type of ref="module.php?name=Lexikon&file=search&eid=1&query=ISDN">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 ref="module.php?name=Lexikon&file=search&eid=1&query=T1">T1. Elsewhere the PRI has 31 user channels, usually divided into 30 B channels and 1 D channel and is based on the ref="module.php?name=Lexikon&file=search&eid=1&query=E1">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)
