ITU-T F 64-1993 DETERMINATION OF THE NUMBER OF INTERNATIONAL TELEX CIRCUITS REQUIRED TO CARRY A GIVEN VOLUME OF TRAFFIC《为运送给定容量的报务量确定所需国际用户电报电路的数目》.pdf

1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 (b) that the use of tables for the determination of the number of circuits as a function of the traffic to be dealtwith during the busy hour is an established practice in all Administrations, and is a convenient means of indicating astandard;(c) that inte

2、rnational telex circuits may be selected either at manual positions, or via automatic switchingequipment, particularly where subscriber-to-subscriber selection is employed between two networks;unanimously declares(1) that Administrations should use Tables 1/F.64 or 2/F.64 below, according to the sys

3、tem of selectionemployed (i.e. manual selection or automatic selection) in the international service;(2) Administrations should aim for full availability of circuits on intercontinental and ARQ radio routesoperated with signalling in accordance with Recommendations U.1, U.11, U.12 and U.20. Where an

4、 Administration isunable to provide the full availability, it should provide an availability to achieve not less than 90% of the fullavailability capacity relative to the number of circuits on the route at a grade of service of one in 50.1 Introduction1.1 Table 1/F.64 shows values for manual traffic

5、 carried. If for the purpose of design (as distinct from themaintenance of rapid service) it is desired to obtain values for offered traffic in erlangs, these may be determined byadding the respective values of lost traffic to the figures for carried traffic in Table 1/F.64.1.2 Table 1/F.64 is direc

6、tly applicable only to full-availability groups of circuits that are operated either wholly asbothway circuits, or wholly as undirectional circuits.1.3 Tables 2/F.64 shows values for traffic offered in the automatic service and is directly applicable to full-availability groups and groups with avail

7、abilities between 10 and 50.Given the traffic offered (A) in erlangs and the availability (K), the number of circuits required to provide a lossprobability (B) of 0.02 may be determined from. Table 2/F.64. Groups of up to 200 circuits and availabilities of 10, 20,30, 50 and N circuits (N circuits co

8、rresponding to full availability) are covered. The method of applying the table isshown in Figure 1/F.64.1.4 Where groups of circuits are divided into bothway and unidirectional components, the division and number ofcircuits in each component will be agreed between Administrations.2 Fascicle II.4 -

9、Rec. F.64TABLE 1/F.64Traffic capacity table for manually selected telex circuits (Note 1)Number of circuitsAverage intensity for traffic carried in the busy hour, expressed in erlangs, fora grade of service (probability of loss) of:1 in 10 (Note 2) 1 in 30 (Note 3) 1 in 50 (Note 3)abcd12345678910111

10、213141516171819200.20.91.52.33.20.0660.430.891.492.172.923.774.665.566.477.398.319.2410.211.112.113.013.914.915.90.0340.330.761.291.922.673.444.255.095.936.797.678.579.4810.411.312.313.214.115.0Note 1 Table 1/F.64 makes allowance for the manual operator to continue the search for a free line over th

11、e group of circuitsconcerned for a period of 30 seconds if all are engaged, after which the search is abandoned and the call suspended.Note 2 Column b of Table 1/F.64 will, in general, only be used in respect of small groups of circuits of considerable length, havingdue regard to the desire to provi

12、de a rapid service, as well as to economic considerations.Note 3 In all other cases the figures of column c shall be used in preference to those of column d.Fascicle II.4 - Rec. F.64 3TABLE 2/F.64Traffic capacity table for automatic circuitsK 10 20 30 50 . NN12345678910111213141516171819202122232425

13、26272829303132333435363738394041424344454647484950A5.085.686.296.907.528.158.779.4010.010.711.312.012.613.313.914.615.215.916.517.217.818.519.219.820.521.121.822.523.123.824.425.125.826.427.127.828.429.129.830.431.113.213.914.715.416.216.917.718.419.219.920.721.522.223.023.824.625.326.126.927.728.42

14、9.230.030.831.632.333.133.934.735.536.321.922.723.524.325.126.026.827.628.429.230.030.831.732.533.334.134.935.836.637.438.2 40.30.020.220.601.091.662.282.943.634.345.085.846.617.408.209.019.8310.711.512.313.214.014.915.816.617.518.419.320.221.021.922.823.724.625.526.427.328.329.230.131.031.932.833.8

15、34.735.636.537.538.439.340.34 Fascicle II.4 - Rec. F.64TABLE 2/F.64(contd)K 10 20 30 50 . NN50A31.1 36.3 38.2 40.3 40.3515253545531.832.433.133.834.437.137.938.739.440.239.139.940.741.642.441.142.042.843.744.641.242.143.144.044.9565758596035.135.736.437.137.741.041.842.643.444.243.244.144.945.746.64

16、5.446.347.248.048.945.946.847.848.749.6616263646538.439.139.740.441.045.045.846.647.448.247.448.249.149.950.849.850.651.552.453.350.651.552.553.454.4666768697041.742.443.043.744.449.049.850.651.452.251.652.453.354.155.054.155.055.956.757.655.356.357.258.259.1717273747545.045.746.347.047.653.053.854.

17、655.456.255.856.657.558.359.258.559.460.261.162.060.161.062.062.963.9767778798048.349.049.650.350.957.057.858.659.460.260.060.961.762.663.462.963.864.665.566.464.965.866.867.768.7818283848551.652.252.953.654.261.061.862.663.464.264.365.166.066.867.667.368.269.069.970.869.670.671.672.573.586878889905

18、4.955.556.256.857.565.065.966.767.568.368.569.370.271.071.971.772.673.574.375.274.575.476.477.378.3919293949558.158.859.460.160.769.169.970.771.572.372.773.674.475.376.276.177.077.978.879.779.380.281.282.283.19697989910061.462.062.763.364.073.173.974.775.576.377.077.978.779.680.480.581.482.383.284.1

19、84.185.186.087.088.0Fascicle II.4 - Rec. F.64 5TABLE 2/F.64(concluded)K 10 20 30 50 . NN100A64.0 76.3 80.4 84.1 88.010210410610811065.366.567.869.170.477.979.681.282.884.482.183.885.587.389.085.987.689.491.293.089.991.993.895.797.711211411611812071.772.974.275.576.886.087.689.390.992.590.792.494.195

20、.897.594.896.698.3100.1101.999.6101.6103.5105.5107.412212412612813078.179.380.681.983.294.185.797.399.0100.699.3101.0102.7104.4106.1103.7105.5107.3109.1110.9109.4111.3113.3115.2117.213213413613814084.585.787.088.389.6102.2103.8105.4107.0108.7107.9109.6111.3113.0114.7112.7114.5116.3118.1119.9119.1121

21、.1123.1125.0127.014214414614815090.892.193.494.796.0110.3111.9113.5115.1116.7116.5118.2119.9121.6123.4121.7123.5125.3127.1128.9128.9130.9132.9134.8136.815215415615816097.298.599.8101.1102.4118.3120.0121.6123.2124.8125.1126.8128.5130.3132.0130.7132.5134.3136.1137.9138.8140.7142.7144.7146.616216416616

22、8170103.6104.9106.2107.5108.8126.4128.0129.6131.2132.9133.7135.4137.2138.9140.6139.7141.5143.3145.1146.9148.6150.6152.6154.5156.5172174176178180110.0111.3112.6113.9115.2134.5136.1137.7139.3140.9142.3144.1145.8147.5149.2148.7150.5152.3154.1155.9158.5160.4162.4164.4166.4182184186188190116.4117.7119.0120.3121.6142.5144.1145.7147.3148.9151.0152.7154.4156.2157.9157.7159.6161.4163.2165.0168.3170.3172.3174.3176.3192194196198200122.8124.1125.4126.7128.0150.6152.2153.8155.4157.0159.6161.3163.1164.8166.5166.8168.6170.4172.2174.1178.2180.2182.2184.2186.2