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 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. 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 one D-channel using an E1 line (Europe/rest of world). Each B-channel carries data, voice, and other services. The D-channel carries control and signaling information, Caller ID, via the SS7 Signaling Network.

The Primary Rate Interface channels are typically used by medium to large enterprises with digital PBXs to provide them digital access to the Public Switched Telephone Network (PSTN). The 23 B-channels can be used flexibly and reassigned when necessary to meet special needs such as video conferences. The Primary Rate user is hooked up directly to the telephone company central office.

Contact a Carrier Consulting ISDN PRI Voice Specialist toll free (800) 987-4000 to learn more about the lowest prices for PRI service.