I Figure 7-4: Leased Line Speeds, Continued North American Digital hierarchy Line Speed Typical Transmission Medium 1.544 Mbps 2-Pair Data-Grade UTP Fractional t1 128 kbps, 256 kbps, 2-Pair Data-Grade UTP 384 kbps, 512 kbps 768 kbps Bonded T1s(multiple A few multiples of2-Pair Data-Grade UTP T1s acting as a single 544 Mbps line) T1 lines are very widely used Fractional t1 lines offer lower speeds for companies that need them Two or three T1 lines can be bonded for higher speeds T1, Fractional T1, and Bonded T 1s are the most widely used leased lines7-9 Figure 7-4: Leased Line Speeds, Continued Line Speed Typical Transmission Medium Fractional T1 128 kbps, 256 kbps, 384 kbps, 512 kbps, 768 kbps 2-Pair Data-Grade UTP T1 1.544 Mbps 2-Pair Data-Grade UTP North American Digital Hierarchy Bonded T1s (multiple T1s acting as a single line) A few multiples of 1.544 Mbps 2-Pair Data-Grade UTP T1 lines are very widely used. Fractional T1 lines offer lower speeds for companies that need them. Two or three T1 lines can be bonded for higher speeds. T1, Fractional T1, and Bonded T1s are the most widely used leased lines