Patent ID: 6456705
Filing Date: 2002-09-24
Classification: H04M,H04Q

Abstract:
A digital key telephone system connected to a communication network through an office line, accommodating a plurality of extension lines connected to extension terminals, and having a function of switching and connecting the office line to the plurality of extension lines or the extension lines to each other by a time switch and, simultaneously with switching/connection, sending a predetermined tone signal generated by a tone generator to a corresponding office line or extension line through the time switch,said time switch comprising: digital level conversion means for converting an input signal level of each time slot into a different signal level and outputting the signal; and level control means for, in sending the tone signal to the office line or the plurality of extension lines, controlling a gain of said digital level conversion means in accordance with a state of the office line or extension line to which the signal is to be sent.