Communication terminal device adapted to physical characteristics of telecommunication network and method for adapting communication terminal device to physical characteristics of telecommunication network

Abstract

The communication terminal device includes a handset, a central controller, a telephone network adaptor unit for converting analog signals transmitted/received between telecommunication network and the communication terminal device into digital signals, an interface unit physically isolating the central controller from the telephone network adaptor unit, and transmitting/receiving the converted digital signals between the central controller and the telephone network adaptor unit, and a telephone circuit unit which transmits the voice signals generated by processing the digital signals received from the telephone network adaptor unit to a handset through the interface unit and transmits the digital signals generated by processing the voice signals received from the handset to the telephone network adaptor unit through the interface unit. The telephone network adaptor unit is controlled by the central controller and changes the physical characteristics of the analog signals to be adapted to the physical characteristics of the telecommunication network.

1 . An apparatus connectable to a Public Switched Telephone Network (PSTN), comprising:
 a memory storing information regarding signal frequency characteristics of voice signals demanded by a plurality of designate-able nations, one of which can be selected as a designated nation; and   a telephone circuit unit to change voice signals according to the information regarding signal frequency characteristics of voice signals demanded by the designated nation.   
     
     
         2 . The apparatus of  claim 1 , wherein one of the plurality of designate-able nations is selectable via a user operation. 
     
     
         3 . The apparatus of  claim 1 , wherein the telephone circuit unit comprises a digital filter to control a frequency band of the voice signals according to the information regarding signal frequency characteristics of voice signals demanded by the designated nation. 
     
     
         4 . An apparatus connectable to a Public Switched Telephone Network (PSTN), comprising:
 a memory storing information regarding signal magnitude characteristics of side-tone signals demanded by a plurality of designate-able nations, one of which can be selected as a designated nation; and   a telephone circuit unit to change side-tone signals according to the information regarding signal magnitude characteristics of side-tone signals demanded by the designated nation.   
     
     
         5 . The apparatus of the  claim 4 , wherein the telephone circuit further comprises an amplifier for amplifying the side-tone signals, a gain of the amplifier controlled according to information regarding signal magnitude characteristics of side-tone signals demanded by the designated nation.