| 摘要 |
The method consists, for calling mobile units from the management centre, in: having each of the stations send, over a predetermined call channel which is recognisable by a specific call modulation, a call signal including identifiers of the mobile units requested; having the call channel analysed by each mobile unit, these mobile units being set up in advance on this call channel; with each received identifier, having the mobile unit compare this identifier with that specific to the mobile unit in question; and, in the event of a matching comparison, having the mobile unit acknowledge the call, in such a way as to allow the radiotelephony communication to be set up. According to the invention, this method is characterised in that: the call channel of each station is an essentially fixed channel; during the analysis step, the mobile units remain on the frequency of the call channel as long as they recognise the said specific call modulation on it; and the mobile unit acknowledges the call by searching, among the channels of the station other than the call channel, for a free channel which is recognisable by a specific availability modulation, and by sending, on this free channel, an acknowledgement signal, in such a way as to allow setting up of the radiotelephony communication on this free channel.
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