PURPOSE: To relieve the load of a central processing unit having been used for press-to-talk switching control in a conventional system by adding press-to- talk switching information to control information and sending the resulting information to a radio equipment side to apply the switching control of the transmission/reception mode of the radio equipment.
CONSTITUTION: When the press-to-talk switching button 18 of a control panel 12 is depressed by the operator or the like, a press-to-talk switching information imparting circuit 16 imparts press-to-talk switching information to a control signal composed of various parameters required for the transmission. When a radio interface 21 detects the press-to-talk switching information 31 from a received control signal 29, the contact of a press-to-talk switching control relay 22 is closed. When the contact of a press-to-talk switch 25 is closed by interlocking therewith, a radio equipment 24 is switched to the transmission state to send a voice signal 28 sent succeedingly. Thus, the press-to-talk switching control is implemented independently of a central processing unit.
SAITO RYUICHI
OISHI ISAO
NIPPON ELECTRIC ENG