Telephone, its control method, and telephone communication system

A telephone that rejects a call from a predetermined telephone number, the telephone comprising:

• a telephone number memory section that stores a telephone number whose incoming call is allowed and a telephone number whose incoming call is rejected;
• a telephone number identification section that identifies a caller's telephone number;
• a ringing time interval determination section that compares a ringing time interval of an incoming call with a predetermined time interval;
• a telephone number registration section that registers the telephone number whose incoming call is rejected;
• a telephone number collating section that collates an inputted telephone number for calling with a telephone number whose incoming call is rejected;
• and
• a telephone number processing section that turns the telephone number whose incoming call is rejected, which corresponds with the inputted telephone number for calling, to a telephone number whose incoming call is allowed,
• wherein said telephone number registration section stores a telephone number of an incoming call as a telephone number whose incoming call is rejected, in case where the ringing time interval of the incoming call is shorter than the predetermined time interval and the telephone number of the incoming call does not match up with any of the telephone numbers whose incoming calls are allowed.