ameters. To show these interactions the end to end performance of the connec- tion given in Figure 30.4 is considered. For the principal connection Example transmission plan elements the main analogue transmission parameters are identified in Table 30.2. From the discussion in Section 30.6 the impact of each of these parameters on the main end to end performance can This section illustrates the basic steps required in developing a be summarised. Table 30.3 shows these and whether they have any transmission plan for the hypothetical network given in Figure 30.8 impact on the key end to end analogue parameters. For clarity the where the network structure has already been determined. It is also Table does not include crosstalk, non-linear distortion and qd, and assumed that the telephone instruments are provided by the network delay although a similar approach can be adopted for these par- operator. Table 30.3 Effect of network component performance on end to end performance Purameter Network component End to end performance End to end Loss/frequen Noise Sidetone Talker echo Listener echo/stabili Loss(LR) Loss/frequency Input impedance Telephone Local line Linecard Balance impedance Telephone Linecard Noise Balance about Earth Delay 30/12 Transmission planning INTERNATIONAL SLR 1 Talker A Listener B Figure 30.10 Overall Loudness Rating (OLR) The objectives of the plan are to provide the end to end perfor- At this stage preliminary objectives for minimum, maximum and mance to support a telephony service covering both national and median values of SLR and RLR should be identified. These should international calls. be based on the SLR and RLR Recommendations in G.111 and the The recommended steps are as in the following sections. traffic weighted mean value of OLR should lie in the CCITT preferred range of 8dB to 12dB. 30.8.1 Stage 1: Provisional loudness rating values 30.8.2 Stage 2: Delay assessment Ideally a distribution of the delays introduced on routeings between A telephony service is the main aim therefore plan