| 摘要 |
PROBLEM TO BE SOLVED: To enable communication at higher speed than the conventional case with novel communication equipment without exerting any influence upon existent slave communication equipment. SOLUTION: The master equipment (shown in Fig.) of a communication system such as a personal handy phone system(PHS) is provided with a modulator 104 and a demodulator 110 of two systems at conventional speed and much higher speed switchable by changeover switches 103-111. The slave equipment to be newly added has the almost similar configuration. In a link establishment phase, modulating method change request information is notified from the slave equipment to the master equipment together with a communication request. The designation information of a time slot to be used for a communication phase and modulating method designation information are notified from the master equipment to the slave equipment. In the communication phase, the communication is performed while using the designated modulating method and time slot. The slave equipment can select the modulating method corresponding to the required transmission speed. When any modulating method is not designated from the slave equipment, the same modulating method as the modulating method of the link establishment phase is used in the communication phase so that the existent slave equipment having no designating means for the modulating method can be used as it is without being affected. |
