WARNING SYSTEM FOR ERRONEOUS TELEPHONE NUMBER

PURPOSE:To detect an erroneous telephone number by providing a busy tone detecting part, a ringing tone detecting part, and a silence detecting part which detect the state of a line after automatic dialing from a facsimile communication equipment and driving an alarm part if a signal does not come. CONSTITUTION:If the destination device called by a line wire exchange 70 is not the facsimile communication equipment but is a telephone set 80, that is, the telephone number is erroneous, a call signal is sent to the destination side, and an alarm part 17 is started when the frequency of call (dialing) is higher than a certain value in case of no response to the call signal, but a dial part 16 is started if it is lower than the certain value. Since a facsimile signal (audible frequency), which should be generated if the destination device is the facsimile communication equipment, is not transmitted from the telephone set 80, this state is detected (for a prescribed time or longer) by a silence detecting part 153 of a line monitor part 15 of the facsimile communication equipment to drive the alarm part 17, thus warning of the erroneous telephone number.