Abstract: A portable sensor includes (i) a housing; (ii) one or more sensing devices, such as a video camera and/or a gas sensor (iii) a transmitter, electrically coupled to the sensing device(s) for transmitting a signal generated by the sensing devices; and (iv) a power source electrically coupled to, and for supplying electrical power to, the sensing devices, and the transmitter. The sensor is particularly useful for surveillance, inspections, medical emergencies and a variety of different settings in which remote transmission of inspected images is desired.

Abstract: Apparatus for detection of the presence of signalling tones in telephony is provided wherein the output levels for four band-pass filters in the VF band are processed by means of logic circuits to yield a "tone present" decision. Selection of two critical thresholds permits the apparatus to operate optimally within its environment of trading off talk-off immunity with minimum acceptable signal-to-noise ratio.