Presents the meaning of telephone and telephone comunication system. Consist of telephone communication such as telephone , telephone line and telephone exchange. Includes the constraint of telephone cable for instance every telephone have to use copper wire from telephone exchange, it have to put many copper line in the cable as more as it can and make it smaller as possible. Describes the nature constaint of cable , every conductor of electricity work related to size of conductor and distance, the place which far from telephone cable have to use big copper wire.