| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a communication apparatus in which error display of a calling party telephone number can be suppressed. <P>SOLUTION: Direct current direction detection means of a communication apparatus 10 detects change in the direct current direction of a telephone line which connects the communication apparatus with a switchboard. Voltage variation detection means detects voltage variation of the telephone line. First determination means, when change in the direct current direction of the telephone line is detected in a first period in which a reception completion signal is transmitted after the telephone number is received, determines that polarity inversion of the telephone line has occurred during the first period. Second determination means, when voltage variation of the telephone line is detected during a second period in which a call signal for calling the communication apparatus is received after the reception completion signal is transmitted, determines that polarity inversion of the telephone line has occurred during the second period. The second control means controls the received telephone number not to be displayed on display means when it is determined that the polarity inversion of the telephone line has occurred in at least one period of the first period and the second period. <P>COPYRIGHT: (C)2013,JPO&INPIT |
