There are two types of PRI (Primary Rate Interface): T1 PRI and E1 PRI. T1 PRI is commonly used in North America and Japan, offering 23 bearer (B) channels for voice or data and one signaling (D) channel for call control, totaling 24 channels. E1 PRI, widely used in Europe, Asia, and other regions, provides 30 B channels and one D channel, totaling 31 channels. Both types ensure high-quality, reliable digital communication, making them ideal for businesses, call centers, and enterprises requiring efficient and scalable voice connectivity.