<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (January 2016) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (January 2016) (Learn how and when to remove this template message) </Td> </Tr> <P> The Primary Rate Interface (PRI) is a telecommunications interface standard used on an Integrated Services Digital Network (ISDN) for carrying multiple DS0 voice and data transmissions between the network and a user . </P> <P> PRI is the standard for providing telecommunication services to enterprises and offices . It is based on T - carrier (T1) transmission in the US, Canada, and Japan, while the E-carrier (E1) is common in Europe and Australia . The T1 line consists of 23 bearer (B) channels and one data (D) channel for control purposes, for a total bandwidth of 24x64 - kbit / s or 1.544 Mbit / s . The E1 carrier provides 30B - and two D - channels for a bandwidth of 2.048 Mbit / s . The first timeslot on the E1 is used for synchronization purposes and is not considered to be a B - or D - channel . The D - channel typically uses timeslot 16 on an E1, while it is timeslot 24 for a T1 . Fewer active bearer channels, sometimes called user channels, may be used in fractional T1 or E1 services . </P>

What is the full form of p r i