| 摘要 |
PURPOSE:To decrease the opportunity that a call is cut off due to all required channels in busy state by starting the supervision of talking quality in an adjacent radio service area before deterioration of the talking quality takes place and ensuring a required channel for channel switching during talking so as to reduce the time of talking with the deteriorated talking quality. CONSTITUTION:When deterioration of talking quality takes place in a radio talking channel 61A and an exchange station 21A controlling a radio service area 2A discriminates to use a radio talking channel 61B of an adjacent service area, the station 21A gives a command to an automobile telephone set 5 to be moved to a radio talking channel 61B and gives a command to an exchange station 21B controlling a radio service area 2B to close a switch 63B. Then the exchange station 21A opens a switch 63A and closes a switch 65A. Thus, the automobile telephone set 5 continues the talking with a subscriber 7 of a general telephone network through the radio talking channel 61B, the switch 63B, an inter-station trunk 40, the switch 65A and a trunk 64A. |
