Abstract: A communication device carries out a routing operation of data between a first network and a second network. The communication device comprises: a first interface connected to the first network; a second interface connected to the second network; and a processor that assigns an IP address to a user terminal device connected to the first interface in accordance with a DHCP. The processor changes a first lease period of the IP address set when the processor assigns the IP address to the user terminal device in accordance with the change of a network environment.

Abstract: A communication device carries out a routing operation of data between a first network and a second network. The communication device comprises: a first interface connected to the first network; a second interface connected to the second network; and a processor that assigns an IP address to a user terminal device connected to the first interface in accordance with a DHCP. The processor changes a first lease period of the IP address set when the processor assigns the IP address to the user terminal device in accordance with the change of a network environment.

Abstract: A portable telephone apparatus usable both for telephone and hearing music is disclosed, including an antenna for holding communication with a base station or a parent unit, a voice input unit such as a microphone, a voice output unit such as a speaker, an operating unit including keys and a display unit manipulated by a user operating the apparatus, a telephone control unit for modulating a radio signal from the voice input unit and outputting the modulated signal to the antenna and demodulating the radio signal received through the antenna, extracting a voice signal and outputting the voice signal, a chargeable battery for supplying power to the apparatus, a storage unit for storing the compressed music data, a data restoration unit for reading, expanding and reproducing as a music signal the data stored in the storage unit, and a switching unit for selecting the voice signal demodulated by the telephone control unit or the music signal reproduced by the data restoration unit and outputting the selected sig

Abstract: The present invention relates to a navigation sppratus for finding a vehicle location by calculating on the basis of an output data of an acceleration detecting means for detecting a vehicle acceleration.The navigation apparatus provides at least one acceleration detecting means for detecting a vehicle acceleration and stop judge means for judging a vehicle stopping state from the output variation of the acceleration detecting means.