Wireless communications device and control method for wireless communications device

1. A wireless communications device that is a control station for a slave station and that performs encrypted communications using an encryption key and that changes the encryption key using a sequence of encryption key change messages in a predetermined procedure, during a call, the device comprising:

a processor; and

a memory storing a program that, when executed by the processor, causes the wireless communications device to reduce an audio level of audio data until the encryption key is correctly changed in the sequence of encryption key change messages, if the procedure in which the encryption key is changed is not correctly performed due to an error occurring in the sequence of encryption key change messages in the predetermined procedure, in a case where a change of the encryption key is made.

2. The wireless communications device of claim 1 , wherein the program, when executed by the processor, causes the wireless communications device to:

reduce the audio level of the audio data, in a case where a response message in the sequence of encryption key change messages is not received, in the predetermined procedure in which the encryption key is changed.

3. The wireless communications device of claim 1 , comprising:

an audio processor which, in operation, performs control such that the audio level of the audio data is faded out at a predetermined rate in a case where a reception error occurs during communication and such that the audio level of the audio data is faded in at the predetermined rate in a case where the reception error does not occur in a state where the audio level of the audio data is faded out, and performs control such that the audio level of the audio data is muted in a case where a message for an encryption key change is not able to be correctly received and such that the muting of the audio level of the audio data is canceled in a case where the message for the encryption key change is correctly received in a state where the audio level of the audio data is muted.

4. A control method for a wireless communications device that is a control station for a slave station and that performs encrypted communications using an encryption key, the method comprising:

outputting decoded audio data during a call;

changing the encryption key using a sequence of encryption key change messages in a predetermined procedure during the outputting of the decoded audio data;

reducing an audio level of the decoded audio data until the encryption key is correctly changed in the sequence of encryption key change messages in a case where the procedure is not correctly performed due to an error occurring in the sequence of encryption key change messages in the predetermined procedure.

5. A wireless communications device that is a control station for a slave station, the wireless communications device comprising:

a wireless communicator which, in operation, performs wireless communications with the slave station using an encryption key, wherein the encryption key is changed using a sequence of encryption key change messages in a predetermined procedure;

a processor; and

a memory storing a program that, when executed by the processor, causes the wireless communications device to reduce an audio level of audio data until the encryption key is correctly changed in the sequence of encryption key change messages, if the procedure in which the encryption key is changed is not correctly performed due to an error occurring in the sequence of encryption key change messages in the predetermined procedure during a call using the encryption key.

6. The wireless communications device of claim 5 ,

wherein the program, when executed by the processor, causes the wireless communications device to control the audio level of the audio data based on prescribed information during the call using the encryption key, and

wherein the prescribed information is on the presence or absence of a reception error in an audio signal that is transmitted from the slave station.

7. The wireless communications device of claim 5 ,

wherein the program, when executed by the processor, causes the wireless communications device to control the audio level of the audio data based on prescribed information during the call using the encryption key, and

wherein the prescribed information is on whether or not a message that is to be transmitted from the salve station in order to change the encryption key is received.

8. The wireless communications device of claim 5 ,

wherein the program, when executed by the processor, causes the wireless communications device to control the audio level of the audio data based on prescribed information during the call using the encryption key, and

wherein the prescribed information is on a reception state of the slave station, which is attached to an audio signal that is transmitted from the slave station.

9. The wireless communications device of claim 6 ,

wherein the program, when executed by the processor, causes the wireless communications device, in a case where the reception error occurs, to lower the audio level of the audio data to a degree to which the audio level is faded out, during the communication using the encryption key.

10. The wireless communications device of claim 7 ,

wherein the program, when executed by the processor, causes the wireless communications device, in a case where the message that has to be transmitted from the slave station is not received, to lower the audio level of the audio data to a degree to which the audio level is muted, during the communication using the encryption key.