    Patent document 1: JP-2003-198713 A (corresponding to US-2003/0114202)    Patent document 2: JP-2003-218996 A
A cellular phone compliant to a Bluetooth (registered trademark) communication function becomes widely used. In connection with it, an in-vehicle handsfree apparatus for establishing a Bluetooth communication link with the above cellular phone has been offered (for example, Patent documents 1, 2).
In such an in-vehicle handsfree apparatus, when the cellular phone receives an incoming signal via a communication network while establishing the Bluetooth communication link between the in-vehicle handsfree apparatus and the cellular phone, the cellular phone sends an incoming notice signal or call to the handsfree apparatus. Upon receiving it, the handsfree apparatus executes the handsfree incoming control to give a notice for indicating that the cellular phone has received the incoming call while prohibiting the cellular phone from outputting an incoming ringer tone.
In contrast, an in-vehicle navigation apparatus having a handsfree function connectable with multiple communication terminals is offered. A cellular phone may receive an incoming signal from a communication network in a state where the in-vehicle navigation apparatus cannot execute a handsfree incoming control relative to the incoming signal. In such a case, the navigation apparatus has a difficulty in executing a handsfree incoming control. The user needs to operate the cellular phone, instead of operating the navigation apparatus, to answer the incoming signal. Herein, it is not a problem if the navigation apparatus is operated while the vehicle is parked or stopped; however, if the vehicle is running, it becomes a cause to interfere the safety of driving the vehicle. This is not desirable.