ISDN Primary Rate Interface (PRI) Overview ISDN Basic Rate Interface (BRI) is a digital connection that provides three digital channels. These channels consist of two 64 kbps Bearer channels (B-channels) and one 16 kbps signaling channel (D-channel). This 2B+D connection is known as a Digital Subscriber Loop (DSL). The DSL can be configured to provide line access, trunk access, or packet data transmission. Line Access provides a digital connection from a system ISDN BRI card to ISDN terminals that comply with CCITT, ANSI, ETSI NET-3 and ETS 300 403 (including EuroISDN), INS NET-64 (including Japan D70), National ISDN-1 (NI-1), 1TR6, and Numerics VN2 standards; for example, terminals are telephone sets, fax machines, personal computers, and video display terminals. Trunk Access provides Meridian Customer Defined Network (MCDN) TIE trunk connectivity between Large and Small Systems, QSIG ISDN BRI trunk connectivity, and CO/DID trunk connectivity to local exchanges that support Numerics VN3, 1TR6, ETSI NET-3 and ETS 300 403 (EuroISDN), INS NET-64 (including Japan D70), Australia ETSI, and Asia-Pacific protocols.
The Primary Rate Interface (PRI) is a standardized telecommunications service level within the Integrated Services Digital Network (ISDN) specification for carrying multiple DS0 voice and data transmissions between a network and a user. PRI is the standard for providing telecommunication services to offices. It is based on the T-carrier (T1) line in the US and Canada, and the E-carrier (E1) line in Europe. The T1 line consists of 24 channels, while an E1 has 32.
PRI provides a varying number of channels depending on the standards in the country of implementation. In North America and Japan, it consists of 23xB (B channels (be/s). In Europe and Australia, it is 30xB + 1xD on an E1 2.048 Mbit/s. One timeslot on the E1 is used for synchronization purposes and is not considered to be a B or D channel.
Primary Rate Interface is for large organizations with 30 bearer channels and 2xD (D channel [delta channel] [23 64-kbit/s digital channels + 1 64-kbit/s signaling/control channel) on a T1 [1.544 Mbit (PRI]), for larger applications. Both rates include a number of B-channels and a D-channel. Each B-channel carries data, voice, and other services. The D-channel carries control and signaling information.
The Primary Rate Interface (PRI) consists of 23 64-kbit/s B-channels and one 64-kbit/s D-channel using a T1 line, often referred to as “23B + D”, (North American and Japanese standard) or 30 B-channels and two D-channels using an E1 line (Europe/rest of world), often referred to as “30B + 2D”. A T1 Primary Rate Interface user would have access to a 1.472-Mbit/s data service. An E1 Primary Rate Interface user would have access to a 1.920 Mbit/s data service. Larger connections are possible using PRI pairing.
1PRI module applies to PLANET IPX-2200, IPX-2500v2, IPX-2500v1 and IPX-2100v1 IP PBX system with one port. This port has four LEDs (light-emitting diodes), which is assembled on the mainboard.
