Patent attributes
The present invention is to provide a surveillance apparatus for monitoring the situation of a visitor through a mobile phone, which comprises a monitor assembly including a microprocessor, a digital/analog converter connected to the microprocessor, an electric bell, a microphone, and a speaker. If the electric bell is pressed, a visit signal will be sent to the microprocessor. After the microprocessor has received the visit signal, a notice signal is sent immediately from a switchboard through at least one base station to a mobile phone. After the mobile phone is connected, a bidirectional signal communication can be made between the mobile phone and the microphone and the speaker.