Communication apparatus

A communication apparatus comprising a master device connected with a plurality of outside lines for performing an outside communication of communication data between said master device and said plurality of outside lines, and a plurality of slave devices wirelessly connected with said master device for performing a communication of said communication data between said master device and said plurality of slave devices by using a spread spectrum communication method, said communication of said communication data between said master device and said plurality of slave devices being performed for each communication frame which indicates an unit of said communication on the basis of said spread spectrum communication method, said communication data including at least one of a first-type communication data and a second type communication data,

• (i) said master device comprising:
• a first communication device for performing said outside communication of said communication data between said master device and said plurality of outside lines;
• a converting device for converting a first format of said communication data received from said plurality of outside lines into a second format which can be handled by said master device, and for converting said second format of said communication data received from said plurality of slave devices into said first format which can be handled by said plurality of outside lines;
• an allocating device for dividing said communication frame into at least a first slot and a second slot for allocating said first slot to said communication data to be used for performing a first communication between said master device and a first slave device among said plurality of slave devices, and for allocating said second slot to said communication data to be used for performing a second communication between said master device and a second slave device among said plurality of slave devices, said first slot including a first sending slot and a first receiving slot, said second slot including a second sending slot and a second receiving slot;
• and
• a second communicating device for performing simultaneously said first communication of said communication data between said master device and said first slave device by using said first slot, and said second communication of said communication data between said master device and said second slave device by using said second slot, and
• a determining device for determining whether said communication data received from said plurality of outside lines by said first communicating device is first-type communication data or second-type communication data, and for determining whether said communication data received from said plurality of slave devices by said second communicating device is first-type communication data or second-type communication data,
• wherein said allocating device allocates said first slot to the communication of the first-type communication data and allocates said second slot to the communication of said second-type data on the basis of a determination by said determining device,
• wherein said allocating device changes a length of said first slot in accordance with the presence or absence of the second-type communication data determined by said determining device, and forms only said first slot if said determining device determines that no second-type communication data is present,
• (ii) each of said plurality of slave devices comprising:
• a generating device for generating said communication data to be send to said master device;
• a selecting device for selecting a slot allocated to said communication data to be used for performing said first or second communication between said master device and said each of plurality of slave devices from among at least said first slot and said second slot;
• and
• a third communicating device for performing said first or second communication of said communication data between said master device and each of plurality of slave devices by using said selected slot, wherein each of first slot comprising a hop period for stabilizing communication frequency, the hop period of the first slot used by a slave device which communicates voice data is longer than the hop period of the first slot used by the master device and a slave unit which communicates non-voice data.