PURPOSE: To recognize the presence of an event at a specific location with dialing from an optional private branch telephone set by controlling an even detection signal sensed by a sensor and outputting the signal to a private branch telephone network.

CONSTITUTION: An event presence notice equipment 1 consists of a sensor section 2, a control section 4 and a relay operating section 6 and connects to a private branch exchange 12 through a telephone line 11. Then the sensor section 2 senses a physical event to send a detection signal to the control section 4. The control section 4 samples periodically the detection signal and controls a level and a time of a notice signal based on the obtained value to send the notice signal to the relay operating section 6. The relay operating section 6 outputs an off-hook level and the on-hook level by on/off of a relay contact point to the telephone line 11 with the private branch telephone set 12. Thus, the event automatically sensed by the sensor 2 is recognized by dialing from an optional private branch telephone set 13.