Patent ID: 7957519

Claim:
A method for controlling a private branch exchange system including a private branch exchange and a plurality of extension phones, the private branch exchange receiving caller information through a communication line and storing the caller information as an incoming call log therein, the plurality of the extension phones being divided into a plurality of groups and the extension phones in a same group having a same incoming call group number, the method including the following steps of: when the private branch exchange receives a call for the incoming call group number through the communication line, transmitting an incoming call signal of the call to all of the extension phones in the group corresponding to the incoming call group number by the private branch exchange; if none of the extension phones in the group corresponding to the incoming call group number have answered the call, causing all of the extension phones to display no answer message thereon; and when the private branch exchange receives an incoming call log display request from at least one of the extension phones in the group corresponding to the incoming call group number, causing the at least one of the extension phones in the group corresponding to the incoming call group number to display the caller information received by the private branch exchange thereon through the communication line.