Abstract: A distance notification device includes a first and a second positional information acquiring units that acquire positional information on a user and peripheral users respectively at a predetermined time interval; a distance calculating unit that calculates respective distances between the user and the peripheral users based on the positional information; a distance determining unit that determines whether each of the distances is equal to or longer than a predetermined distance; a coordinate information calculating unit that calculates and update coordinate information on a meeting point based on the positional information; and a display that displays various images; wherein the display further notifies, by updating sequentially, the user of directional information toward the meeting point when a number of the peripheral users at a distance equal to or longer than the predetermined distance from the user is equal to or larger than a predetermined number.

Abstract: A radio device includes a storage unit, a group call control unit, and a cipher key generation unit. The storage unit is configured to store therein a plurality of primary cipher keys, a plurality of pieces of device information, and a plurality of pieces of group information. The group call control unit is configured to perform a group call with radio devices belonging to a first group using a primary cipher key. The cipher key generation unit is configured to generate a secondary cipher key that is different from the primary cipher key when one or more radio devices belonging to the first group are selected during the group call. The group call control unit performs a temporary group call with the selected radio devices by switching the primary cipher key to the secondary cipher key.

Abstract: A wireless device having an action mode that automatically repeats, at a fixed temporal interval, a sending action of sending a voice and a receiving action of receiving the voice includes a voice recorder configured to record the voice therein when the voice is input from a microphone during execution of the action mode, a sending controller configured to send the voice input in the sending action during the execution of the action mode, and a recording controller configured to control recording in the voice recorder, wherein the sending controller is further configured to send the voice recorded in the voice recorder when the voice is not input from the microphone in the sending action.

Abstract: A radio device includes a storage unit, a group call control unit, and a cipher key generation unit. The storage unit is configured to store therein a plurality of primary cipher keys, a plurality of pieces of device information, and a plurality of pieces of group information. The group call control unit is configured to perform a group call with radio devices belonging to a first group using a primary cipher key. The cipher key generation unit is configured to generate a secondary cipher key that is different from the primary cipher key when one or more radio devices belonging to the first group are selected during the group call. The group call control unit performs a temporary group call with the selected radio devices by switching the primary cipher key to the secondary cipher key.

Abstract: A wireless device having an action mode that automatically repeats, at a fixed temporal interval, a sending action of sending a voice and a receiving action of receiving the voice includes a voice recorder configured to record the voice therein when the voice is input from a microphone during execution of the action mode, a sending controller configured to send the voice input in the sending action during the execution of the action mode, and a recording controller configured to control recording in the voice recorder, wherein the sending controller is further configured to send the voice recorded in the voice recorder when the voice is not input from the microphone in the sending action.