System for selectively transmitting messages to passers-by

Claim 2

In a system comprising at least one means for wirelessly transmitting recorded information messages in a first area proximal thereto and at least one mobile means roaming around a second area including said first area for receiving said transmitted messages when in said first area; a method for selectively establishing a link for said receiving means to receive said messages from said transmitting means when inside said first area, said method comprising the steps of: (a) sending a control signal from said transmitting or said receiving means for pick-up by said receiving or transmitting means whenever said receiving means substantially enters said first area; (b) picking said control signal up at said receiving or transmitting means and responding thereto by transmitting said information message from said transmitting means into said first area; (c) enabling said receiving means to receive said message from said transmitting means; (d) detecting reception of said information message at said receiving means and, in response thereto, continue sending said control signal to said receiving or transmitting means; (e) continue transmitting said information message into said first area while said control signal is picked up at said receiving or transmitting means; (f) terminating the link between said transmitting and receiving means when said receiving or transmitting means stops receiving said control signal; and (g) stop sending said control signal upon termination of the transmitted message.

Claim 3

A method according to claim 1, wherein said control signal is transmitted by said transmitting means substantially continually into said first area, said further comprising the steps of detecting said control signal at said receiving means upon entry into said first area and sending a "listening" control signal from said receiving means back to said transmitting means to cause said transmitting means to begin transmission of said message.

Claim 4

A method according to claim 1, wherein said recorded messages and control signals are transmitted wirelessly via radio signals.

Claim 5

A method according to claim 1, wherein said recorded messages are transmitted wirelessly via radio signals and control signals are transmitted wirelessly via optical infrared signals.

Claim 6

A method according to claim 1, wherein said recorded messages are voice messages.

Claim 7

A method according to claim 1, comprising the steps of: (a) sending a "listening" control signal from said receiving means for pick-up by said transmitting means whenever said receiving means substantially enters said first area; (b) picking said "listening" signal up at said transmitting means and responding thereto by transmitting said information message from said transmitting means into said first area; (c) enabling said receiving means to receive said message from said transmitting means; (d) detecting reception of said information message at said receiving means and, in response thereto, continue sending said "listening" control signal to said transmitting means; (e) continue transmitting said information message into said first area while said "listening" signal is picked up at said transmitting means; and (f) terminating the link between said transmitting and receiving means when said transmitting means stops receiving said "listening" control signal.

Claim 8

A method according to claim 6, wherein said receiving means interrupts sending said "listening" signal for a preselected time interval in response to detecting said message being interrupted in step (c).

Claim 9

A method according to claim 6, further comprising the steps of: (g) issuing a "sending" control signal from said transmitting means into said first area in response to picking said "listening" signal up at said transmitting means; and (h) detecting said "sending" control signal at said receiving means and responding thereto by enabling reception of said information message thereat.

Claim 10

A method according to claim 8, wherein said transmitting means includes a plurality of audio messages recorded therein and transmits a sequentially different message each time said transmitting means detects a new such "listening" control signal from a said receiving means entering said first area.

Claim 11

A method according to claim 8 in a system including a plurality of transmitting means at different fixed locations associated with respective first areas, wherein each of said transmitting means includes different messages prerecorded therein.

Claim 12

A method according to claim 10, wherein each said transmitting means is adjusted to transmit at a respective preselected transmission carrier frequency and said "sending" control signal transmitted in step (g) encodes the carrier frequency of said message to be transmitted in step (b) and said step (h) includes decoding said carrier frequency from said "sending" control signal and tuning said receiving means to the decoded carrier frequency.

Claim 13

A method according to claim 10 in a system including a plurality of receiving means roaming generally randomly in said second area, wherein said steps (a) through (h) are carried out for each receiving means entering a respective one of said first areas associated with a corresponding transmitting means.

Claim 16

A system according to claim 13, wherein said storage means contains a plurality of said information messages recorded therein and each fixed unit further includes selector means for sequentially selecting one of said recorded messages in response to said detecting means detecting a new "listening" control signal in said receiving means in said fixed unit.

Claim 17

A system according to claim 13, wherein said detecting means in each fixed unit further includes flip-flop means for generating said "transmit enable" signal when set, said flip-flop means connected to be set by said receiving means of said fixed unit in response to the presence of said "listening" control signal thereat and to be reset by the transmitted message ending.

Claim 18

A system according to claim 13, wherein: (a) each fixed unit further includes: (vi) second transmitting means for transmitting a "sending" control signal in response to said receiving means in said transmitting means receiving said "listening" control signal from one such mobile unit, said end-of-message means inhibiting transmission of said "sending" control signal in response to detecting said end of said information message being transmitted; and (b) each mobile unit further includes: (iv) second receiving means for detecting said "sending" control signal from said fixed unit and generating an "audio enable" signal in response thereto, (v) detector means for sampling said output from the first receiving means and deactivating said "audio enable" signal in response to termination or interruption of the received message, said detector means further responding to the presence of said message at said output of said first receiving means to enable said transmitting means of said mobile unit to continue sending out said "listening" control signal to said receiving means of said fixed unit.

Claim 19

A system according to claim 16, wherein each fixed unit includes means for setting a carrier frequency for said first transmitting means thereof to transmit said information message, and means for encoding said carrier frequency in said "sending" signal; and wherein each mobile unit includes decoding means for decoding said carrier frequency in said "sending" signal for tuning said first receiving means thereof to said decoded carrier frequency.

Claim 20

A system according to claim 17, wherein said setting means in said fixed unit comprises a tone generator connected to said second transmitting means to cause the latter to transmit said "sending" control signal of a frequency encoding said carrier frequency, and said decoding means in said mobile unit comprises a control frequency decoder circuit to determine said carrier frequency.

Claim 21

A system according to claim 18, wherein said carrier frequency is settable to one of two preset carrier frequencies and said frequency decoder circuit comprises two frequency discriminator devices tuned to a different preset frequency of said tone generator.

Claim 22

A transmitter unit for use in a system comprising a plurality of similar transmitter units spaced apart from one another for wirelessly transmitting recorded information messages in respective first areas proximal thereto within a second area traversed by a plurality of mobile receiver units for receiving a particular one of said transmitted messages when in one of said first areas, said transmitter unit including for assisting in selectively establishing a link with one of said receiving units to receive one of said information messages from said transmitting unit when inside said first area proximal to said transmitter unit, said assisting means comprising; storage means for storing signals determining the contents of at least one information message, said information message including a beginning and an end, receiving means for receiving a "listening" control signal from one such mobile receiver unit entering into said first area, detecting means for detecting the presence of said "listening" control signal at said receiving means and generating in response thereto a "transmit enable" signal, first transmitting means responsive to said "transmit enable" signal to retrieve an information message from said storage means and transmit the retrieved message into said first area, end-of-message means for detecting said end of said information message being transmitted to thereby inhibit said "transmit enable" signal until said detecting means receives said "listening" control signal from a different one such mobile receiver unit, and second transmitting means for transmitting a "sending" control signal in response to said receiving means in said transmitting means receiving said "listening" control signal from one such mobile unit, said end-of-message inhibiting transmitting a "sending" control signal in response to detecting said end of said information message being transmitted.

Claim 23

A transmitter unit for use in a system comprising a plurality of similar transmitter units spaced apart from one another for wirelessly transmitting recorded information messages in respective first areas proximal thereto within a second area traversed by a plurality of mobile receiver units for receiving a particular one of said transmitted messages when in one of said first areas, said transmitter unit including for assisting in selectively establishing a link with one of said receiving units to receive one of said information messages from said transmitting unit when inside said first area proximal to said transmitter unit, said assisting means comprising; storage means for storing signals determining the contents of at least one information message, said information message including a beginning and an end, receiving means for receiving a "listening" control signal from one such mobile receiver unit entering into said first area, detecting means for detecting the presence of said "listening" control signal at said receiving means and generating in response thereto a "transmit enable" signal, first transmitting means responsive to said "transmit enable" signal to retrieve an information message from said storage means and transmit the retrieved message into said first area, end-of-message means for detecting said end of said information message being transmitted to thereby inhibit said "transmit enable" signal until said detecting means receives said "listening" control signal from a different one such mobile receiver unit, and second transmitting means for transmitting a "sending" control signal in response to said receiving means in said transmitting means receiving said "listening" control signal from one such mobile unit, said end-of-message inhibiting transmitting a "sending" control signal in response to detecting said end of said information message being transmitted.

Claim 24

A transmitter unit according to claim 20, wherein said storage means contains a plurality of said information messages recorded therein and said transmitter unit further includes selector means for sequentially selecting one of said recorded messages in response to said detecting means detecting a new "listening" control signal in said receiving means.

Claim 25

A transmitter unit according to claim 21, and further including means for setting a carrier frequency for said first transmitting means thereof to transmit said information message, and means for encoding said carrier frequency in said "sending" signal.

Claim 26

A transmitter unit according to claim 22, wherein said carrier frequency setting means comprises a tone generator connected to said second transmitting means to cause the latter to transmit a "sending" signal of a frequency encoding said carrier frequency.

Claim 27

A transmitter unit according to claim 23, wherein said carrier frequency may be set to one of two preset carrier frequencies.

Claim 28

A transmitter unit according to claim 20, wherein said detecting means further includes flip-flop means for generating said "transmit enable" signal when set, said flip-flop means connected to be set by said receiving means of said fixed transmitter unit in response to the presence of said "listening" control signal thereat and to be reset by the transmitted message ending.

Claim 29

In a system comprising a plurality of generally fixed transmitter units for wirelessly transmitting pre-recorded information messages in respective first areas proximal thereto within a second area generally including all of said first areas, a mobile receiver unit comprising: transmitting means for sending out a "listening" control signal for detection by one such fixed transmitter unit upon entry of said receiver unit into said first area corresponding to said transmitter unit, first receiving means for receiving an information message transmitted by said transmitter unit into said first area associated therewith and having an output for relaying the received message in useful form, second receiving means for detecting a "sending" control signal from said fixed unit and generating an "audio enable" signal in response thereto, wherein said second receiving means further includes means for decoding a carrier frequency in said "sending" signal for tuning said first receiving means thereof to said decoded carrier frequency, detector means for sampling said output from the first receiving means and deactivating said "audio enable" signal in response to termination or interruption of the received message, said detector means further responsive to the presence of said message at said output of said first receiving means to enable said transmitting means to continue sending out said "listening" control signal.

Claim 30

In a system comprising a plurality of generally fixed transmitter units for wirelessly transmitting pre-recorded information messages in respective first areas proximal thereto within a second area generally including all of said first areas, a mobile receiver unit comprising: transmitting means for sending out a "listening" control signal for detection by one such fixed transmitter unit upon entry of said receiver unit into said first area corresponding to said transmitter unit, first receiving means for receiving an information message transmitted by said transmitter unit into said first area associated therewith and having an output for relaying the received message in useful form, second receiving means for detecting a "sending" control signal from said fixed unit and generating an "audio enable" signal in response thereto, wherein said second receiving means further includes means for decoding a carrier frequency in said "sending" signal for tuning said first receiving means thereof to said decoded carrier frequency, detector means for sampling said output from the first receiving means and deactivating said "audio enable" signal in response to termination or interruption of the received message, said detector means further responsive to the presence of said message at said output of said first receiving means to enable said transmitting means to continue sending out said "listening" control signal.

Claim 31

A receiver unit according to claim 26, wherein said second receiving means includes a multivibrator circuit for generating said "receive enable" signal.

Claim 32

A receiver unit according to claim 26, wherein said second receiving means further includes a plurality of parallel frequency discriminator circuits for decoding a carrier frequency in said "sending" signal for tuning said first receiving means thereof to said decoded carrier frequency, said frequency discriminator circuits having an output indicative of a decoded carrier frequency, the outputs of said plurality of discriminator circuits are connected to trigger said multivibrator circuit.

Claim 33

A receiver unit according to claim 26, wherein said receiver unit is user-portable and said output of said receiving means is connected to an audio amplifier and to earphone means to enable a user to hear said transmitted message in audible form.

Claim 34

A receiver unit according to claim 26, and further including a timer means connected between said detector means and said transmitting circuit for inhibiting said transmitting means from sending said "listening" control signal during a preselected time after said detector means determines that reception of said transmitted message has terminated.

Claim 35

A receiver unit according to claim 26, wherein said decoding means comprises a frequency decoder circuit.

Claim 36

A receiver unit according to claim 21, wherein said frequency decoder circuit comprises two frequency discriminator devices tuned to a different predetermined frequency.

Claim 37

A receiver unit according to claim 26, wherein said receiver unit is mounted on a respective cart and said output of said receiving means is connected to an audio amplifier and a loudspeaker for propagating said transmitted message in audible form to a cart user.

Claim 38

A receiver unit according to claim 33, wherein said cart is provided with sensor means for outputting a signal indicative of cart movement and said receiver unit further includes means responsive to said cart movement signal to power-down said receiver unit during substantially no movement of said cart for more than a preselected time.

Claim 39

In a system comprising at least one means for wirelessly transmitting recorded information messages in a first area proximal thereto and at least one mobile means roaming around a second area including said first area for receiving said transmitted messages when in said first area; a method comprising the steps of: (a) sending a "listening" control signal from said receiving means for pick-up by said transmitting means whenever said receiving means substantially enters said first area; (b) picking said "listening" signal up at said transmitting means and responding thereto by transmitting said information message from said transmitting means into said first area; (c) enabling said receiving means to receive said message from said transmitting means; (d) detecting reception of said information message at said receiving means and, in response thereto, continue sending said "listening" control signal to said transmitting means; (e) continue transmitting said information message into said first area while said "listening" signal is picked up at said transmitting means; and (f) terminating the link between said transmitting and receiving means when said transmitting means stops receiving said "listening" control signal; (g) issuing a "sending" control signal from said transmitting means into said first area in response to picking said "listening" signal up at said transmitting means and (h) detecting said "sending" control signal at said receiving means and responding thereto by enabling reception of said information message thereat; and (I) stopping issue of said "sending" control signal upon termination of the transmitted message.

Claim 40

In a system comprising at least one means for wirelessly transmitting recorded information messages in a first area proximal thereto and at least one mobile means roaming around a second area including said first area for receiving said transmitted messages when in said first area; a method comprising the steps of: (a) sending a "listening" control signal from said receiving means for pick-up by said transmitting means whenever said receiving means substantially enters said first area; (b) picking said "listening" signal up at said transmitting means and responding thereto by transmitting said information message from said transmitting means into said first area; (c) enabling said receiving means to receive said message from said transmitting means; (d) detecting reception of said information message at said receiving means and, in response thereto, continue sending said "listening" control signal to said transmitting means; (e) continue transmitting said information message into said first area while said "listening" signal is picked up at said transmitting means; and (f) terminating the link between said transmitting and receiving means when said transmitting means stops receiving said "listening" control signal; (g) issuing a "sending" control signal from said transmitting means into said first area in response to picking said "listening" signal up at said transmitting means and (h) detecting said "sending" control signal at said receiving means and responding thereto by enabling reception of said information message thereat; and (I) stopping issue of said "sending" control signal upon termination of the transmitted message.