| 摘要 |
PURPOSE:To inform the user of an automobile telephone terminal of a hand-off destination or a hand-off disable state when a radio channel in use is deteriorated and hand-off is caused in an automobile telephone exchange system. CONSTITUTION:An automobile telephone exchange 1 controls radio base stations 2-6. A database 7 has data of relation of position of a radio base station under its control. When the automobile telephone terminal in the service area hands off, the cellular telephone exchange 1 references the database 7 to inform of a hand-off prediction information and a geographical information for hand-off destination. The hand-off prediction information and the geographical information are transmitted/received during talking by interrupting momentarily a voice signal. Upon the receipt of the hand-off prediction information, an automobile telephone terminal 8 rings a prediction tone. Furthermore, the automobile telephone terminal 8 has a position display section 81, on which the received geographical information is displayed. |
