Patent ID: 8878665

Claim:
A method of interconnecting alarms in a structure, without installing a third conductor, said method comprising the steps of: installing a transceiver between an alarm and said alarm's commercial power source, by: disconnecting the alarm from two power conductors that supply the alarm's power; connecting the transceiver to the two power conductors; connecting the alarm to two power input conductors of the alarm; and connecting the alarm's alarm output conductor to the an alarm input of the transceiver; similarly installing a second transceiver between a second alarm and said alarm's commercial power source; power and the radio signal, as an RF alarm signal, enter circuit ( 4 ) through wires ( 6 B and 6 W); the RF alarm signal goes through a power line interface ( 20 ); the RF alarm signal is filtered through a collision protection ( 40 v ); if said RF alarm signal passes the collision protection, said RF alarm signal is transmitted to receiver interface ( 42 ); a band limited amplifier ( 44 ) amplifies only a specific frequency used as an alarm frequency of the RF alarm signal; a sharp band pass filter ( 46 ) further screens and narrows the frequency; said RF alarm signal is then input into band limited amplifier ( 48 ) which amplifies said RF alarm signal; the amplified said RF alarm signal is input to a discriminator comparator ( 50 ), which ascertains that the input RF alarm signal is indeed the specific frequency used as the alarm frequency; the RF alarm signal is passed from discriminator comparator 150 to noise eliminating microcomputer ( 10 ), and if it is determined not to be noise, the RF alarm signal is sent to output drive ( 24 ) which actuates sound warning ( 26 ); the noise eliminating microcomputer ( 10 ) also passes the RF alarm signal to drive enable ( 30 ), which actuates frequency stable oscillator ( 32 ) to output the RF alarm signal; the RF alarm signal is amplified by power amplifier ( 34 ); the amplified RF alarm signal then passes through band filter ( 36 ) to further narrow RF alarm signal; the narrowed RF alarm signal then passes through impedance matching transformer ( 38 ); the narrowed RF alarm signal then passes to powerline interface ( 20 ); where the RF alarm signal is again injected into power lines ( 6 B and 6 W); the RF alarm signal then is transmitted down the power line, to other alarm transceivers, which might otherwise be out of range of an alarm transceiver which transmitted the original RF alarm signal to the circuit ( 4 ).