This Recommendation contains a recommendation for the mean active speech level to be used for setting the levels of announcement machines and speech synthesis systems in the telephone network. A level of –19 dBm0 is recommended, which presumes that the SLR of the telephones in the network is 8 dB, the long-term target value (referred to a 0 dBr point). If the present SLR in a national network is different, the recommended level can be adjusted, using a formula supplied, to a level consistent with that of live speech in the network. The recommended level is defined at the 0 dBr point, and to measure the level a speech voltmeter conforming to the requirements of Method B speech level meters in Recommendation P.56 should be used.