Method of selectively connecting a received telephone call by utilizing a calling party number in a keyphone system

摘要

A method of making the telephone call by retrieval of a call signal using a calling party number in keyphone system by transmitting data of a calling party number to a keyphone terminal to display the received calling party number on a display window of the keyphone terminal when a keyphone main device receive a call through a central office line, and connecting the corresponding line; sensing the reception of a called signal calling the keyphone terminal on the telephone call through a central office line; sensing the input of the key for selecting a waiting call after off-hook ring service is provided for informing the presence of the waiting call to the keyphone terminal on line when the called signal is sensed; transmitting data of the calling party number corresponding to the waiting call to the keyphone terminal to display the calling party number on the display window when the input of the key for selecting the waiting call is sensed; and interrupting the call on the telephone call and connecting the selected waiting call to the keyphone terminal when the input of key requesting telephone call with the displayed waiting call is sensed. Therefore, the telephone call can be rapidly made for an important or impending call received through central office lines.