An apparatus and technique for providing a monitoring alarm telephone which not only automatically dials a predetermined alarm notification telephone number upon activation of a suitable alarm device (e.g., tripping of a motion detector), but which also provides audible monitoring of the secured premises using the automatically dialed telephone call. In one embodiment, an open channel is established between the monitoring alarm telephone and a called telephone allowing sounds from the secured pr...

Solid stage apparatus for the detection of synchronism between line and bus voltages in order to permit safer interconnection therebetween is disclosed. A first comparator circuit constantly monitors the magnitude of the vector difference between the line voltage and the bus voltage and generates a first enabling signal whenever the magnitude of the vector difference voltage is below a predetermined value. The first enabling signal will continue to be generated until the magnitude of the vector ...

A battery charging circuit, a method of charging a battery and a battery-powered electronic device employing the circuit or the method. In one embodiment, the battery charging circuit includes a charging switch coupled between a base interface of the battery-powered electronic device and a battery thereof to be charged. When closed, the charging switch provides a conductive path for charge current from the base interface to the battery. The charge current is based on an input voltage of the batt...