Patent ID: 7050556
Filing Date: 2006-05-23
Classification: H04M

Abstract:
1. A key telephone unit comprising: (a) at least three connection ports to each of which a telephone can be connected through communication lines, at least one of the communication lines being a public switched line, each of said connection ports having a respective predetermined identification number; (b) a voice guidance transmitter constructed and arranged to be able to inform a first telephone connected to a first of the connection ports of the predetermined identification numbers of vacant said connection ports when the first telephone makes a call, the voice guidance transmitter also being constructed and arranged to be able to inform the first telephone connected to the first connection port of a number of the connection port to which a second telephone making a call to said first telephone is connected; and (c) a controller constructed and arranged so as to be able to connect said first telephone to said second telephone when the second telephone is making a call to the first telephone, the controller also being constructed and arranged so as to be able to connect the first telephone to a third telephone, based on said numbers of vacant connection ports; wherein the connection ports, the voice guidance transmitter, and controller are constructed and interconnected to allow all communication between each of the connection ports that is not connected to the public switched line and the telephone connected to that port to take place using only two signal lines.