1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 2 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%2!0(94%,%2!0(G0G042!.3-)33)/.35-!29G0G0/(b) that User Classes of Services 1 and 2 in Recommendation X.1 should be taken into account;(c) that the rates and codes given in Recommendation R.101 should be ta
2、ken into account;(d) that Recommendations R.20, R.50, R.57, R.58, R.120, R.121 and S.3 should be taken into account,unanimously declares the viewIn planning international point-to-point and switched telegraph communications, Administrations should usethe following as a guide. The individual recommen
3、dations referred to should be taken into account.Note 1 Most of the figures given were derived using the laws of addition of distortion appropriate to analoguetransmission equipment MCVFT, however were another law is known to apply TDM, then the appropriate law ofaddition should be used (see Recomme
4、ndation R.11).Note 2 Most of the figures given relate to start-stop distortion but some, R.20, R.120 and R.58 for trunkdistortion, relate to isochronous distortion. As a first approximation, isochronous and start-stop distortion may beconsidered to be equivalent for small values. However the individ
5、ual Recommendations should be taken into accountin each case.In the following examples:T is the customers terminal,M is a modem to Recommendation R.20,represents the transmit distortion from the given point,represents the margin at the given point,represents the distortion introduced between the given points.2 Fascicle VII.1 - Rec. R.122 Fascicle VII.1 - Rec. R.122 3 4 Fascicle VII.1 - Rec. R.122 Fascicle VII.1 - Rec. R.122 5
