plexed together, the total user capacity is 3 × 774 × 8 ×8000, or 148.608 Mbps. For an OC-3072 line: Gross data rate = 51.84 × 3072 =159252.48 Mbps. SPE data rate = 50.112 × 3072 =153944.064 Mbps. User data rate = 49.536 × 3072 =152174.592 Mbps. 35. VT1.5 can modate 8000 frames/sec ×3 columns ×9 rows ×8 bits = 1.728 Mbps. It can be used to modate DS-1. VT2 can modate 8000 frames/sec ×4 columns ×9 rows ×8 bits = 2.304 Mbps. It can be used to modate European CEPT-1 service. VT6 can modate 8000 frames/sec ×12 columns ×9 rows ×8 bits = 6.912 Mbps. It can be used to modate DS-2 service. 36. The OC-12c frames are 12 × 90 =1080 columns of 9 rows. Of these, 12 × 3 =36 columns are taken up by line and section overhead. This leaves an SPE of 1044 columns. One SPE column is taken up by path overhead,
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