Abstract: Apparatus for tracking and recovering humans utilizes an implantable transceiver incorporating a power supply and actuation system allowing the unit to remain implanted and functional for years without maintenance. The implanted transmitter may be remotely actuated, or actuated by the implantee. Power for the remote-activated receiver is generated electromechanically through the movement of body muscle. The device is small enough to be implanted in a child, facilitating use as a safeguard against kidnapping, and has a transmission range which also makes it suitable for wilderness sporting activities. A novel biological monitoring feature allows the device to be used to facilitate prompt medical dispatch in the event of heart attack or similar medical emergency. A novel sensation-feedback feature allows the implantee to control and actuate the device with certainty.

Abstract: An emergency call system includes a wireless telecommunication network having predetermined radio channels, at least one wireless emergency call transmission device for reading emergency data and transmitting the data in an emergency call message on at least one of the radio channels, and at least one emergency call receiver device. The at least one emergency call receiver device receives and evaluates the emergency call message, and triggers at least one alarm function and/or further conducts the emergency data to an alarm center connected to the wireless telecommunication network. The system may also be embodied in a wire-bound network.

Abstract: An improved device for monitoring the presence of a person, animal or piece of property within a predefined space. The invention consists of a means for attaching to a monitoree, a transmitter assembly containing electronic circuitry which periodically sends a coded signal a limited distance to a remote detection unit. If the expected signal is not received, indicating that the person or object has been removed from the predefined space, an alarm condition is indicated. The transmitter is securely attached to the item being monitored by means of a non-stretchable, flexible, circuit strap which indicates an alarm condition when the strap is tampered with. The strap is locked into the transmitter assembly by a latch key which also triggers the transmitter to begin sending signals. The device is easily reattached or transferred to another item to be monitored by monitoring personnel by removing the latch key and inserting a new latch key after the device has been reinstalled.

Abstract: A signalling device is installed in headwear, such as an athletic helmet, and includes sensing devices for detecting linearly and rotationally directed impacts above a selected magnitude. The sensing devices trigger the signalling device so as to produce a perceivable signal, thereby alerting observers that a potentially injurious impact has occurred.

Abstract: A child finder basically consists of a transmitter which is concealingly attachable to a child's body and which sends a signal to a conventional receiver so that the child's location can be continually monitored. The transmitter will typically be carried in an article of jewelry, such as a watch, bracelet, ring, or the like, and will use a special on/off switch which allows the transmitter to be activated only when the jewelry is being worn by the child. The switch includes a reciprocal push button which closes the transmitter's electrical circuit when depressed, and the button is spring-biasedly moved away from electrical contact with the transmitter's circuit when the article of jewelry is not being worn.

Abstract: An anti-removal monitoring device which may be strapped to a person's appendage or to a piece of equipment. Once activated, the device transmits a signature encoded RF signal distinguishable from others to be monitored by a receiving station. If either the person or the device moves or is removed to a range out of signal reception, or if tampered with as by cutting the strap, such alteration of the normal signal is detected at the receiving station. The device comprises, in one embodiment, a transmitter housing for electrical connection to a base in a manner sealing the connection against the elements, and with a biased piston movably mounted within the base for operative connection with both ends of the strap and for activation of the transmitter only upon completed securement of the strap ends about the appendage or equipment and into the base.

Abstract: An in vivo video camera system and an autonomous video endoscope are described. Each system includes a swallowable capsule, a transmitter and a reception system. The swallowable capsule includes a camera system and an optical system for imaging an area of interest onto the camera system. The transmitter transmits the video output of the camera system and the reception system receives the transmitted video output.

Abstract: A radio tracking system adapted for domestic pets wearing collars. A transmitting unit slips over the animal's collar, and has accommodation for a variety of collar dimensions. A hand held receiver unit indicates strength of signals sent from the transmitting unit through illumination of a plurality of LED lamps. The receiver is pointed in a variety of directions, until a direction is identified which results in the strongest indicated signal, which illuminates more lamps than are illuminated when the receiver is pointed in other directions. This indicates location of the transmitter, and hence the animal, regardless of distance between the transmitter and receiver. Periodic monitoring of signal strength assures that the owner is successfully tracking the animal. Both transmitter and receiver have their own battery power sources and power switches. The transmitter has a battery power level indicator for ascertaining reliability thereof.

Abstract: A swimming training device may be part of an overall training system. The device is deployable releasably in a swimming cap and can receive electromagnetic wave signals. The device can then convert the signals into electrical charges which are then translated into audible sound. The system includes the cap with the receiving device and a transmitting source. The transmitting source allows the broadcasting of verbal instructions, as well as music and timing signals.

Abstract: A mount for supporting a microphone on a helmet having an outer shell and for use with a transmission cable. The microphone is mounted on a flexible boom carrying leads connected to the microphone. The transmission cable carries electrical conductors. The mount includes an attachment assembly having a surface with a contour which conforms to the outer shell of the helmet. The attachment assembly is provided with a sleeve-like member adapted to receive the flexible boom and a retainer for receiving the transmission cable. Connectors are carried within the attachment assembly for electrically connecting the electrical conductors from the transmission cable to the leads to the microphone. A layer of an adhesive material is carried by the surface of the attachment assembly and is adapted to fasten the attachment assembly to the outer shell of the helmet. The layer of adhesive material permits the fastening of the attachment assembly to the helmet without impairing the structural integrity of the helmet.

Abstract: A three part security access arrangement in which the first part is associated with an authorized person in the form of, for example a belt buckle, the second part is attached to a valuable item, for example a wallet, and the third part is associated with an area of restricted access, such as a car. Access to the restricted area is denied unless all three parts are in close proximity. If either of the first or second parts are absent the third part will not allow access to the restricted area. The first and second parts incorporate means for providing an audible alarm if they are separated by greater than a pre-determined distance.

Abstract: A proximity alert and direction indicator is provided that allows an observer to monitor the proximity of a subject under surveillance, particularly a child. The subject wears a transmitter removeably attached to the shoe. The observer wears a receiver-containing bracelet. The receiver contains a proximity detector with threshold set that emits an audible sound when the distance between the subject and the observer exceeds some preset distance. The receiver also contains a direction finder with graphic display that shows the observer the direction to the subject.

Abstract: A helmet assembly for providing an indication when a predetermined axial compressive force tending to cause serious injury to the wearer is applied thereto. The assembly comprises a rigid helmet having a lower rim for at least partially encircling the head of the wearer. The helmet is defined by an exterior surface including a crown areal. A transmitting device is carried by the helmet for transmitting a signal to a remote location when a predetermined amount of axial compressive force is applied to the crown area. Receiving means disposed remotely from the helmet receives the signal transmitted by the transmitting device.

Abstract: A security system for monitoring an area under surveillance includes a transmitter for generating radio frequencies (RF) signals when actuated using an actuator. A sensing station receives the RF signals from the transmitter. A monitoring station generates video signals of the area under surveillance and provides one end of a duplex audio communications system. A control station, coupled to the sensing station and the monitoring station, actuates the monitoring station in response to the RF signals sensed by the sensing station. The control station includes an opposite end of the duplex audio communications system and a display for displaying the video signals.

Abstract: A signalling device is installed in headwear such as an athletic helmet and includes triaxially sensitive sensors for detecting impacts above a selected magnitude and for providing a signal characteristic of the magnitude and direction of an impact.

Abstract: A survival radio for use for transmitting and receiving information for search and rescue having an improved structural housing assembly for increased reliability to prevent moisture and water intrusion, while permitting use of the device in any ambient air pressure. The housing assembly includes a tongue and sealed groove connections joined by deforming the tongue in a pliable state, housing assembly apertures covered by a deformable flexible sealable plastic panel to permit manual actuation of internal switches and an air vent that has a porous plug permitting air pressure equalization between the inside and outside of the housing assembly, while preventing water intrusion.

Abstract: A transmitter assembly is characterized by a buckle including fasteners for holding a strap and the buckle together on an appendage of an individual independent of a transmitter. The buckle also includes latches for attaching the transmitter to the buckle after the buckle is strapped to the individual. An optical fiber running through the strap is held by the fasteners with the ends of the fiber in predetermined positions relative to the buckle. The transmitter covers the strap fasteners, rendering the fasteners inaccessible to the individual, and aligns an emitter and sensor on the transmitter housing with the ends of the optical fiber in the predetermined positions. The ends of the strap are aligned adjacent one another by the buckle, so the buckle adds little to the length of the strap, permitting length measurements without considering the buckle contribution.

Abstract: A miniature electronic security tag is affixed to the ankle of a newborn infant. The tag contains an RF transmitter and digital encoding circuit. On a periodic basis, the tag transmits a unique encoded identity signal to receivers strategically placed within the hospital. The tag is attached to the infant with a security element having a plurality of conductors which form a plurality of complete electrical circuits while the tag is in place. Attempts to remove the tag by cutting or stretching the security element are detected by the encoder circuit, causing a change in the digital code which is transmitted. Receivers are interconnected to a central monitoring computer which continuously determines the identity and location of each infant. In the event an unauthorized person attempts to leave the hospital with an infant, or if the tag is removed, an alarm is sounded.

Abstract: A hand lamp for examining e.g. underbodies, brakes and wheel bearings of motor vehicles in test stands comprises a housing with a grip, at least one energy storage disposed in said housing, a light source with reflector, and switching elements for switching said light source on and off, wherein on the housing (1) at least one transmitting element (8) for remote control of specific components of the test stand is arranged which is connected to the energy storage (4) and the actuating switches (11, 12) via an electric control circuit (10).

Abstract: A medical alert pendant for use as a wireless remote actuation device in an emergency alarm system or the like includes a housing with a circuit board assembly and a resilient mounting and sealing membrane mounted therein. The housing includes an upper housing section which has an opening in the surface thereof, and a lower housing section. The circuit board assembly includes a power source, a signal transmitter and a depressible switch which activates the transmitter. The membrane is positioned between the housing sections and includes a flexible button which is disposed in the housing opening and juxtaposed to the switch on the circuit board assembly. The depression of the flexible button will operate the switch on the circuit board. The membrane includes a first peripheral seal which seals the juncture between the housing sections and a secondary seal which seals the opening in the upper housing section.

Abstract: In a timepiece provided with means to set the time, dates and an alarm time, and display means to indicate functions, means are foreseen to enter messages and announcements. Via a transmitter built into the watch, these messages can be conveyed to a corresponding receiver. At the same time the timepiece is equipped to receive messages, it being possible to receive messages transmitted by another corresponding transmitter. These messages can be indicated by display means which are housed in the timepiece. Thus this timepiece can be used as a means of communication.

Abstract: The present invention relates to a bicycle helmet and communication device for use by children. The invention includes a bicycle helmet having a notch extending from a boundary edge upwardly toward a crown portion. A sleeve is positioned within, and affixed to, the notch. A communication module having an adjustable slide, an earpiece, an antenna, and a boom having a microphone is positioned proximal to the notch for positioning, and adjustably attaching, the slide to the sleeve. The adjustable engagement between the slide and sleeve permits the positioning of the earpiece over the ear and the microphone proximal to the mouth of a child wearing the bicycle helmet and communication device. A power module having a transmitter and a receiver is remotely attached to the communication module by a cable. The power module is adapted for engagement to a user's belt. The microphone is connected to the transmitter which is voice activated by an individual.

Abstract: An electrical circuit comprising means for receiving an input signal for encoding or modulating and amplification. Multiple amplification stages including at least one transconductance amplifier are provided. There are means for having the input signal modulate the oscillator constituted by the multiple amplification stages to provide a 360.degree. phase-shifted signal at a predetermined frequency. Gain control means are also provided for developing level for permitting oscillation under conditions including at least the conditions of turn on of the circuit and other operating conditions. The gain control means includes a transistor and resistor network for adjusting the gain to sustain the oscillation. The transistor and resistor also regulate amplification of an intermediate stage of the amplifier. The preamplifier directly converts an EKG and/or other signals to linearized control currents which modulate the oscillator.

Abstract: A non-erasing audio and/or video tamper-proof recorder is mounted on a belt secured to the body of the taping person, and uses a preidentified recording substrate such as a tape or disk or cassette of which its assigned code identity is maintained in separate distant locked records and stationary files thereof by separate security storage personnel after recording is completed on the recording substrate. There is body mounting structure that secures the recorder in a security fashion avoiding ability to rapidly remove the recorder and/or its enclosed recording substrate from the body of the taping person. The recorder includes multiple coordinated turn-off switching elements requiring use of both hands to terminate (turn-off) taping. The recorder contains a microphone and/or video lense positioned in an orientation for recording events occuring substantially in front of the person wearing the mounted recorder.

Abstract: A system and method for locating patients in a hospital using M different frequency patient transmitters and N fixed location antennas within the hospital for receiving the patient signals. The received signals for each antenna are separated from the signals received by the other N-1 antennas, and the signal strength of each signal received by each antenna is measured. The received signal strength of each antenna is processed to determine which of the antennas received the strongest signals from each of the patient transmitters. Alternatively, the approximate location within the hospital of each operating patient transmitter is determined since the antennas are in fixed locations and the layout out of the hospital is known. In other embodiments, each of the antennas have a different modulation pattern to enable identification of which of the antennas receives which signals from the patient transmitters.

Abstract: A hand-held electronic telecommunications device is provided with a grip and protective casing made of elastomeric material for covering the back face and side walls of the device. The casing is provided with finger recesses on its exterior surface to permit the operator to reliably hold and even operate the device with one hand. The casing is constructed so as to be readily applied and even removed, as desired, by the operator himself. The manner by which the casing is supported on the device enables the casing material to avoid having to cover over any area of the front, operational face of the device, where such features as the ear piece, mouthpiece and push buttons are located.

Abstract: The present invention provides a method of operating a hand-held transmitter for controlling vehicle functions. The hand-held transmitter has the ability to emit output signals for controlling both locking devices and drives for closing vehicle openings. A hand-held transmitter emits the output signals for controlling locking devices at a first output power and range and emits output signals for controlling the drives at a second output power and range. The second output power and range are lower than the first output power and range.

Abstract: A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning.

Abstract: The present invention relates to an improved fireman's helmet which includes a surrounding wall structure that defines a head receiving area therein. Mounted within the head receiving area and recessed in the wall structure are front and rear light assemblies as well as a battery pack and control panel.

Abstract: A key-configured transmitter design has a housing for containing the electronics thereof and a key blank which may optionally be cut to conform to the key shape of the vehicle ignition key or any other key the user might otherwise use on a regular basis. In this manner, it is possible to substitute the transmitter of the present invention for a key that the user would otherwise retain in his pocket or purse, thereby obviating the relative inconvenience of prior art transmitters, which require the addition of a transmitter device to their pocket or purse. The key blank serves the dual purpose of a real key such as for operating the vehicle's ignition and also as an antenna for radiating the oscillator signal produced by the transmitter of the invention.

Abstract: A remotely actuatable sports timing system automatically responds to a whistle blown by the sports official to generate a frequency modulated radio signal which is utilized to provide an instantaneous switching signal to actuate the game clock.

Abstract: A portable water activated alert system is disclosed. The system has an RF transmitter and receiver which incorporate special features. Both are battery operated and portable. The receiver includes both an audible alarm and an illuminated directional and proximity indicator.

Abstract: A signal reproducing apparatus operating on a wireless basis and having a status signal multiplexed with audio signals and transmitted to a receiver containing a display, the status signal indicating the current operating status of a recording medium player. On receiving the status signal, the display indicates the current operating status of the recording medium player so that the user may accordingly control the player from a distance without the intervention of wires.

Abstract: A digital signal transmitter which is mounted upon a rigid panel by resiliently deformable strips such as double-sided adhesive or springs. The mounting is such that a button is disposed adjacent a switch contained within the transmitter structure. The entire apparatus is then worn by a person upon a belt-like structure in such a way that upon muscular expansion by the person wearing the structure, the button closes the switch causing the transmitter to emit a radio frequency signal. The radio frequency signal may then be received by a transponder or other electronic device which amplifies and converts the signal and directs it toward a central station.

Abstract: An intraoral controller senses electromyographic signals within the oral cavity which are produced as a result of movement and contraction of the tongue muscle. Active and reference electrodes pairs act as sensors for electromyographic signals which are processed into control signals. The electrodes are mounted on a substrate within the oral cavity. Signals from the electrodes are transmitted by telemetry or by wires to an electromyographic signal processor which is connected to a device to be controlled.

Abstract: An apparatus is provided for monitoring the location of a person and for determining whether the person is in distress. The apparatus includes a transmitter and a transceiver, which are adapted to be worn at different locations on the person's body. The transmitter normally transmits a first electromagnetic signal, which is detectable by the transceiver and by at least one remote receiver. When the person is in distress, the transmitter transmits a second electromagnetic signal in lieu of the first signal. The transceiver is responsive to the second signal for generating a third electromagnetic signal, which also indicates that the person is in distress. The remote receiver is responsive to either or both of the second and third signals for generating an alarm signal indicating the distress condition.

Abstract: An electronic device (FIG. 1) includes a sensor (17) for determining when the electronic device (FIG. 1) is being worn by a user and when the elecronic device (FIG. 1) is not being worn by the user. A first altering device (21) provides a first alert and a second altering device (22) provides a second alert. An alert selection device (16) which is coupled to the sensor (17) alternatively activates the first alerting device (21) when the electronic device (FIG. 1) is being worn by the user and the second alerting device (22) when the electronic device (FIG. 1) is not being worn by the user.

Abstract: The invention relates to a radio transmitter holder for use with radio transmitters that are typically used to control radio controlled airplanes. The transmitter holder has a tiltable tray that allows the transmitter antenna to be moved upward and out of the way of people, etc. The tray is suspended from the user by means of shoulder straps. The use of the radio transmitter holder thus allows the user of the radio control the use of both arms which would otherwise be used in holding the radio transmitter.

Abstract: The belt-carried holster includes a slitted back plate engaged by a waist belt. Two pairs of complementary hook and loop flexible fastener strips are connected to the back plate and interconnected in pairs in cross-overlapping fashion, for containment of a cassette player against the back plate. At least some of the fastener strips are connected indirectly to the back plate, via flexible cords, which may be slightly elastic.

Abstract: A simplex radio-accessories interface connector (30) connects the simplex radio (10) having a speaker amplifier (102) and a push-to-talk (PTT) detector (103) to accessories which include an earpiece speaker (107) and a PTT switch (110). The connector (30) has a first connector mating assembly (25a-d and 84a-d) for coupling the connector (30) to the radio (10) and a second connector mating assembly (44a-c and 48a-c) for coupling the connector (30) to the accessories. Inside the connector (30), a receive audio line (104a) couples the speaker amplifier (102) to the earpiece speaker (107) and a PTT detect line (122) couples the PTT detector (103) to the PTT switch (110). At the second connector mating assembly (44a-c and 48a-c), the receive audio (104a) and the PTT detect (122) lines are combined (44a and 48a).

Abstract: A personal security system includes at least one movable transmitter adapted to produce an emergency signal transmission when activated and a plurality of transceivers adapted to receive emergency signal transmissions from the movable transmitter. False alarms are avoided by inhibiting multiple transmissions by a movable transmitter within a predetermined time period.

Abstract: A headset assembly is described, of the type which includes a headband with earphones for delivering sound to the wearer, a microphone into which the wearer talks, and a "push-to-talk" switch that is operated when the wearer wishes to talk, whcih facilitates operation of the switch. The switch (24) has an actuator part (30) extending from one of the sides of the headset, such as the left side, to a location above the left shoulder of the wearer. The wearer activates the switch by lifting his left shoulder to press on the actuator part of the switch. The switch is preferably closed by depressing the actuator part, and extends in a downward-outward direction at an angle of about 30.degree. from the vertical, so the natural lifting of the shoulder causes the shoulder to move along the direction of depression of the switch actuator part.

Abstract: A method for using an underground mine communication system to effect minewide communication and an intrinsically safe current limiter circuit for insuring that electrical equipment in the system will not cause incendiary conditions. The underground mine communication system comprises a plurality of repeaters and medium frequency radios, including mobile, portable and personal-carried radios, coupled to electrical conductors and natural waveguides existing in the earth by tuned loop antennas. Messages transmitted by the radios are carried to the repeaters by the conductors or coal seam waves. The repeaters amplify, replicate and retransmit the message at two different frequencies for transmission of the message to a surface base station and to other radios in the system. A paging system, which has a separate set of repeaters, is also coupled to the network of electrical conductors and natural waveguides by tuned loop antennas. The paging system alerts miners to contact the surface base station.

Abstract: The device has a source of acoustic signals placed beneath the hull of the boat, a beacon, an alarm pack worn by the navigator around the neck. If the navigator falls overboard, an acoustic sensor built into the pack detects the emission of the source and actuates the jettisoning of the beacon by remote control. This beacon has a measuring head fitted out with a directional acoustic sensor and a compass capable of computing information on the position of the beacon, transmitted by radio to a control box fixed in the boat. As the beacon is supposed to be near the castaway or man overboard, he is thus found.

Abstract: In a preferred embodiment, a pair of tap shoes each having toe and heel taps, associated with each tap there being an audio-pickup transducer mounted one adjacent each tap, connected by signal-carrying wiring to a common electronic radio-wave transmitter and power-source mechanism that receives and sends the signal received from the respective transducers to a radio-wave receiver and amplifying and speaker mechanism spaced-away from the tap shoes such that tapping sounds of the taps on a hard surface are received, amplified and broadcast through speakers.

Abstract: A carrying bag assembly having a carrying bag for carrying personal items and a telephone receiver/transmitter unit attached to the carrying bag. The receiver/transmitter unit can be connected to a telephone line by means of a wire with a plug on one end. A telephone handset is attached to the receiver/transmitter unit by means of a cord. The handset can be attached to the handle of the carrying bag by two pieces of material that wrap around the handset and attach to one another. A keypad is located on the outer surface of the carrying bag for dialing the telephone.

Abstract: A tag for use with an individual monitoring system. The tag is worn by an individual being monitored, preferably on the ankle or leg where it can be concealed by the clothing of the individual. The tag is fully self contained and sealed. The circuits of the tag periodically generate an identification signal that includes an identification code. The identification signal modulates a stable RF signal that is transmitted in bursts of data words to a receiver associated with a field monitoring device (FMD) located at the monitoring location. In turn, the FMD may randomly establish communication with a central processing unit (CPU) located at a central monitoring location. Other information is included in the identification code of the tag, such as information indicating that an attempt has been made to remove the tag from the individual. The tag is held in place near the skin of it's wearer by a conductive strap that wraps around the leg or other limb of the individual.

Abstract: A high speed digital telemetry system (10) includes a transmitter (12) and a receiver (14), at least one of which is adapted for use in an implantable device. The transmitter includes a data encoder (14), modulator (16), transmitting coil (20), and transmitting coil drive circuit (18). The data encoder examines prescribed incoming data bits and prior encoded data bits, generating an encoded data stream (36) that includes a data transition only when a prescribed correlation is noted amongst the examined bits. The modulator modulates a carrier signal (34) with the encoded data stream, causing a phase reversal of the carrier at each data transition of the encoded data stream. The transmitting coil drive circuit applies the modulated carrier (38) to the transmitting coil. The receiver includes a receiving coil (22) and associated amplifier (24) and bandpass filter (26) for detecting the transmitted modulated carrier.

Abstract: A combined alarm and display belted clinical thermometer being wound on an arm of a user which comprises a thermal sensor to sense the temperature of the user. The sensing signals are converted and the measured value is displayed on an LCD display. The belted clinical thermometer also comprises a comparator which is preset witha reference value to comparing the measured temperature with a reference temperature and; if the measured temperature is significantly larger than the reference temperature, an alarm is triggered to sound. Further to the basic design, the belted clinical thermometer can be equipped with a transmitter which can signal a remote receiver to sound an alarm.

Abstract: Included in the communication apparatus are a face mask covering the eyes, the nose, and mouth of the user and which has a frame holding a transparent viewing shield with a peripheral resilient seal on the frame bearing against the user's face. A relatively low power transmitter is positioned inside the mask adjacent to the air inlet for transmitting a short range signal carrying a communication from the user. A relatively high powered transceiver is carried on the user's person. The communication apparatus also includes a receiver also carried on the user's person tuned to receive the signal of the low powered transmitter and providing an audio output. A voice actuated switch is responsive to the output of the receiver to switch the transceiver from its receiving mode to its transmitting mode.