Car's back-up alarm fitted with speech function

Claim 1

In a vehicle having a body, a source of electric power and a transmission, a vehicular back-up alarm with two-way speech function, comprising: a combination speaker/microphone provided in the rear of the vehicle body; a handset provided at a driver's seat of the vehicle, the handset having a transmitter/receiver, and interrupted wave generating circuit, a preamplifier, a power amplifier, a duplexing circuit and a power stabilizing wave circuit, the handset being operably connected with the source of electric power and with the combination speaker/microphone by an electrical circuit; a back-up switch operably connected with the vehicle transmission and placed in the electrical circuit between the source of electrical power and the handset, the back-up switch being actuable upon engaging of a reverse gear of the vehicle transmission for supplying electrical power to the handset to cause the handset to generate an alarm signal to the combination speaker/microphone; a power switch means provided at the handset and actuable for operably connecting the combination speaker/microphone with the handset for permitting speech at the combination speaker/microphone to be heard at the handset; and a transmit switch means provided at the handset and actuable for operably connecting the handset with the combination speaker/microphone for permitting speech at the handset to be heard at the combination speaker/microphone.