| 摘要 |
A mobile communication system in which a calling terminal transmits coding attribute identification information, and called terminal identification information to a central during call initiation. The coding attribute identifies the compression and coding process used by the calling terminal. A paging request generated by the central switching station is then addressed to the called terminal. The called terminal's response includes coding attribute information identifying its compression and coding process. If the coding and compression processes of the two terminals are the same, communication is conducted without conversion to PCM format. The audio signals transmitted by the calling and called terminals are continuously converted to PCM format at the associated base stations, but if the compression and coding processes of the participating terminals are the same, the unconverted audio signals (with coding attribute identification added) are transmitted. If the compression and coding processes do not match, the PCM signals are transmitted. At each base station, the incoming audio signals pass through PCM-to-native-format code converters. If the coding attribute identification is present in the incoming signal (indicating that the compression and coding processes of the two terminals match), the incoming unconverted audio signal is transmitted to the associated terminal. If the attribute identification is absent, the code converted signal is transmitted.
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