| 摘要 |
PURPOSE:To continue communication by allowing a radio telephone sec to select a zone automatically when the radio telephone set moves to other radio zone than the acting radio zone during communication. CONSTITUTION:When a specific radio telephone set RTEL1 detects itself to be at the outside of a 1st radio zone Z1 for a prescribed time during talking with a specific external line 171, the RTEL1 sends an out-zone signal to a specific connector CE1, which sends the out-zone signal to the master set 1 and the master set 1 replies with the out-zone signal to bring the external line 171 to a self-hold state in which the external line 171 cannot be used other radio telephone sets 3 than the RTEL1 and the RTEL1 selects a control channel from the talking channel after the end of transmission of the out-zone signal, generates a call signal including a zone number allocated to a 2nd radio zone Z2, a connector CE3 in the zone Z2 sends a call signal to the master set 1 when the zone number included in the call signal and the zone number of the zone Z2 to which the CE3 belongs, the master set 1 eliminates the external line 171 in the self-hold state so as to allow the RTEL1 to communicate with the external line 171. |
