By the use of a key in the battery circuit as well as an interrupter or current reverser, signals can be given by breaking up the continuous hum in the telephone into long and short periods.
He pushed the door to a dark room open, using his senses to key in on where the person was.
These trains are produced by pressing the key in the primary circuit of the induction coil for a longer or shorter time' and generating a long or short series of oscillatory electric sparks between the spark balls with a corresponding creation of trains of electric waves.
The necessity for truth is key in all discussions.
She shrugged one shoulder and turned away, jabbing the key in the door.
Dean held the key in his hand and glanced at the check.
Back at the apartment, he paused at the door, key in hand.
The wait lasted less than an hour before Dean heard the metallic sound of a key in the lock.
She wouldn't normally have rented on that basis but he sent her three months payment, in cash, and she left a key in an agreed location.
The signals were sent by cutting up the continuous hum in the telephone into long and short periods in accordance with the Morse code by manipulating the key in the primary circuit.