Used in locomotive communication , pocked intercom telephones , car audio circuits , etc 適用于移動(dòng)通訊、袖珍對(duì)講機(jī),汽車(chē)音響等電路。
百科解釋
An intercom telephone is a special kind of telephone that controls a school intercom system. With that telephone, the workers make the school announcements and can call each classroom's intercom by dialing the room number of that classroom.