Fundamentalsof Telecommunications

62 TRANSMISSION AND SWITCHING: CORNERSTONES OF A NETWORK Table 4.1 Trunk-Loading Capacity, Based on Erlang B Formula, Full Availability Grade of Service 1 in 1000 Grade of Service 1 in 500 Grade of Service 1 in 200 Grade of Service 1 in 100 Grade of Service 1 in 50 Grade of Service 1 in 20 Trunks UC TU UC TU UC TU UC TU UC TU UC TU 1 0.04 0.001 0.07 0.002 0.2 0.005 0.4 0.01 0.7 0.02 1.8 0.05 2 1.8 0.05 2.5 0.07 4 0.11 5.4 0.15 7.9 0.22 14 0.38 3 6.8 0.19 9 0.25 13 0.35 17 0.46 22 0.60 32 0.90 4 16 0.44 19 0.53 25 0.70 31 0.87 39 1.09 55 1.52 5 27 0.76 32 0.90 41 1.13 49 1.36 60 1.66 80 2.22 6 41 1.15 48 1.33 58 1.62 69 1.91 82 2.28 107 2.96 7 57 1.58 65 1.80 78 2.16 90 2.50 106 2.94 135 3.74 8 74 2.05 83 2.31 98 2.73 113 3.13 131 3.63 163 4.54 9 92 2.56 103 2.85 120 3.33 136 3.78 156 4.34 193 5.37 10 111 3.09 123 3.43 143 3.96 161 4.46 183 5.08 224 6.22 11 131 3.65 145 4.02 166 4.61 186 5.16 210 5.84 255 7.08 12 152 4.23 167 4.64 190 5.28 212 5.88 238 6.62 286 7.95 13 174 4.83 190 5.27 215 5.96 238 6.61 267 7.41 318 8.83 14 196 5.45 213 5.92 240 6.66 265 7.35 295 8.20 350 9.73 15 219 6.08 237 6.58 266 7.38 292 8.11 324 9.01 383 10.63 16 242 6.72 261 7.26 292 8.10 319 8.87 354 9.83 415 11.54 17 266 7.38 286 7.95 318 8.83 347 9.65 384 10.66 449 12.46 18 290 8.05 311 8.64 345 9.58 376 10.44 414 11.49 482 13.38 19 314 8.72 337 9.35 372 10.33 404 11.23 444 12.33 515 14.31 20 339 9.41 363 10.07 399 11.09 433 12.03 474 13.18 549 15.25 21 364 10.11 388 10.79 427 11.86 462 12.84 505 14.04 583 16.19 22 389 10.81 415 11.53 455 12.63 491 13.65 536 14.90 617 17.13 23 415 11.52 442 12.27 483 13.42 521 14.47 567 15.76 651 18.08 24 441 12.24 468 13.01 511 14.20 550 15.29 599 16.63 685 19.03 25 467 12.97 495 13.76 540 15.00 580 16.12 630 17.50 720 19.99 26 493 13.70 523 14.52 569 15.80 611 16.96 662 18.38 754 20.94 27 520 14.44 550 15.28 598 16.60 641 17.80 693 19.26 788 21.90 28 546 15.18 578 16.05 627 17.41 671 18.64 725 20.15 823 22.87 29 573 15.93 606 16.83 656 18.22 702 19.49 757 21.04 858 23.83 30 600 16.68 634 17.61 685 19.03 732 20.34 789 21.93 893 24.80 31 628 17.44 662 18.39 715 19.85 763 21.19 822 22.83 928 25.77 32 655 18.20 690 19.18 744 20.68 794 22.05 854 23.73 963 26.75 33 683 18.97 719 19.97 774 21.51 825 22.91 887 24.63 998 27.72 34 711 19.74 747 20.76 804 22.34 856 23.77 919 25.53 1033 28.70 35 739 20.52 776 21.56 834 23.17 887 24.64 951 26.43 1068 29.68 36 767 21.30 805 22.36 864 24.01 918 25.51 984 27.34 1104 30.66 37 795 22.03 834 23.17 895 24.85 950 26.38 1017 28.25 1139 31.64 38 823 22.86 863 23.97 925 25.69 981 27.25 1050 29.17 1175 32.63 39 851 23.65 892 24.78 955 26.53 1013 28.13 1083 30.08 1210 33.61 40 880 24.44 922 25.60 986 27.38 1044 29.01 1116 31.00 1246 34.60 41 909 25.24 951 26.42 1016 28.23 1076 29.89 1149 31.92 1281 35.59 42 937 26.04 981 27.24 1047 29.08 1108 30.77 1182 32.84 1317 36.58 43 966 26.84 1010 28.06 1078 29.94 1140 31.66 1215 33.76 1353 37.57 44 995 27.64 1040 28.88 1109 30.80 1171 32.54 1248 34.68 1388 38.56 45 1024 28.45 1070 29.71 1140 31.66 1203 33.43 1282 35.61 1424 39.55 46 1053 29.26 1099 30.54 1171 32.52 1236 34.32 1315 36.53 1459 40.54 47 1083 30.07 1129 31.37 1202 33.38 1268 35.21 1349 37.46 1495 41.54 48 1111 30.88 1159 32.20 1233 34.25 1300 36.11 1382 38.39 1531 42.54 49 1141 31.69 1189 33.04 1264 35.11 1332 37.00 1415 39.32 1567 43.54 of servicing channels or trunks.