(plural primary rate interfaces)
In Europe, the PRI is delivered via E1 lines (2048 kb/s capacity), with 30 B-channels and 1 D-channel, all of 64kb/s, giving a payload rate of 1984 kb/s and a service rate of 1920 kb/s.
In North America, PRI is delivered via T1 lines using DS-1 signalling (1536 kbs capacity), with 23 B-channels and 1 D-channel, all of 64kbps, giving a payload rate of 1536 kbps and a service rate of 1472 kbps.
In Japan, PRI is delivered via J1 lines, with the same characteristics as North American lines.
primary rate interface - Computer Definition