The Two Types of ISDN

ISDN allows you to integrate voice, data and video flexibly. And we offer two types of ISDN scaled to match your needs. Basic Rate ISDN (BRI) has two channels (B channels) for carrying voice, data or video, and a third channel (the D channel) which carries the call set-up information and low-speed packet data. Each of the B channels is capable of speeds as high as 64kbps.

For applications requiring more bandwidth, such as videoconferencing or higher-speed Internet access, the B channels can be combined, offering up to 128kbps. In addition, multiple phone numbers can be assigned to one ISDN line.

Primary Rate ISDN (PRI) utilizes the same digital technology, but combines 23 B channels with one D channel. In total, PRI service offers 1.54Mbps of bandwidth, the equivalent of a T-1 line. Bandwidth for voice, data and video applications can be allocated dynamically, on a call-by-call basis. So the same channels used for voice calls one minute can be reallocated for a videoconference the next, using your resources more efficiently and economically.