What is ISDN PRI?

ISDN PRI (Integrated Services Digital Network Primary Rate Interface) is a telecommunications interface standard used to provide multiple voice and data channels over a digital telephone line. It is commonly used by businesses to connect their PBX (Private Branch Exchange) systems to the public switched telephone network (PSTN), enabling them to handle a larger volume of simultaneous calls compared to traditional analog lines. A PRI line typically offers 23 B-channels (bearer channels) for voice or data and one D-channel (data channel) for signaling and control.