Household alarm system

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG.
I illustrates the basic components of a household alarm system 10 in accordance with the present invention.
Inside control console 12 transmits actuation signals on alarm actuation signal lines 16A-16D to activate an exterior alarm 14.
The alarm actuation signals are generated by inside control console 12 in response to coded radio trigger signals received on antenna 18 from a portable transmitter 20 or an audio alarm responsive transmitter 22.
Control console 12 is powered by connection to a conventional electrical outlet by a plug-in power supply 24.
A battery backup power source 26, which is kept charged by control console 12, may also be provided.
Control console 12 has only three external switches, an ON/OFF switch 28, a TEST switch 30 and a MUTE switch 32.
Each switch includes an LED indicator for indicating the status of the switch, these being LED 34 for ON/OFF switch 28, the LED 34 being lit when control console 12 is on; LED 36 for TEST switch 30, the LED 36 being lit when the control console is in its test mode; and LED 38 for MUTE switch 32, the LED 38 being lit when an audio siren 40 is deactivated.
Audio siren 40 is part of external alarm 14, which also includes a strobe light 42.
External alarm 14 is preferably mounted to a relatively inaccessible, but highly visible location on the exterior of a house.
External alarm 14 is both powered and actuated directly by control console 12 over alarm actuation signal lines 16A-16D.
It is preferable that there be no external plug in type connection of external alarm 14 to actuation signal lines 16A-16D.
Alarm actuation signal lines 16A-16D include a siren actuation line 16A, a strobe actuation line 16B, a ground line 16C, and a ground sense line 16D.
Ground line 16C and ground sense line 16D form a current loop to allow detection of breakage of actuation lines 16A-16D, such as would occur if external alarm 14 were torn from or removed from the exterior of a house, or where the actuation lines were cut