PRI is a telecommunications standard for carrying voice and data transmissions between the Service Provider Exchange and the customer's Electronic Private Automatic Branch eXchange (EPABX).
It's a Trunk solution of 2 Mbps capacity with 30B-channel which carries data, voice or other services and 1D-channel which carries control and signalling information.
E1 PRI is required to be terminated on a PRI Card in an EPABX.
Each channel can be configured as incoming, outgoing, or two-way, allowing highly effective management of voice traffic.
Each PRI has a Pilot Number, this provides the customer the convenience of having a single number to remember the board line as well for billing