Abstract:
According to one embodiment of the invention, a method of operation involves concurrently receiving spread-spectrum wireless signals from a plurality of sources by a listening device for a hearing-impaired user. These spread-spectrum wireless signals comprise audio in a digital format. The audio is filtered so as to retain audio within a specified audible frequency range set by the hearing-impaired user. The filtered audio is converted into an analog format, and thereafter, is subsequently output for perception by the user. This provides a cost-effective solution for the hearing-impaired in order to avoid unwanted ambient noise normally amplifier by conventional hearing aids.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/547,830 filed Feb. 26, 2004. 
     
    
     BACKGROUND  
       [0002]     1. Field  
         [0003]     Embodiments of the invention relate to an assisted listening device for hearing-impaired persons as well as the system and method of operation thereof.  
         [0004]     2. General Background  
         [0005]     Hearing loss is the third leading chronic disability following arthritis and hypertension. It is estimated that over twenty million Americans have significant hearing loss; many of these persons have forms of hearing loss that affect their ability to distinctly hear sounds during a conversation. As the American population lives longer, there will be more and more people with significant hearing loss.  
         [0006]     Various types of hearing loss, such as nerve-type, can be partially remedied through the use of hearing aids. Conventional hearing aids electronically amplify sound waves received at the ear. Although hearing aids may be tailored to amplify only a particular frequency range to compensate for the specific hearing loss of a particular individual, they also universally amplify all sound, including unwanted ambient noise. As a result, hearing aids provide little assistance during one-to-one or group conversations in a noisy public environment, such as a restaurant or theater for example, because such aids do not differentiate a desired sound (an acoustic signal) from unwanted ambient noise.  
         [0007]     Moreover, conventional hearing aids typically undergo extensive miniaturization so as to discretely conceal their presence. This reduction in size increases overall design and manufacturing costs, which is passed down to the consumers. As a result, a high percentage of hearing-impaired persons cannot afford hearing aids, and thus, may experience a reduced quality of life.  
         [0008]     It would be advantageous to develop a convenient, unobtrusive, discrete and economical listening system that enables normal conversation between a hearing-impaired person and others, even in a noisy ambient environment.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     Embodiments of the invention are illustrated by way of example and not by way of limitation in the accompanying drawings, in which like references indicate similar elements and in which:  
         [0010]      FIG. 1  is a first exemplary embodiment of a hearing-impaired communication system deployed as a spread spectrum wireless network;  
         [0011]      FIG. 2  is a first embodiment of an assisted listening device (L-Device) operating as a receiver;  
         [0012]      FIG. 3  is a perspective side view of the L-Device of  FIG. 2 ;  
         [0013]      FIG. 4  is a second exemplary embodiment of the L-Device of  FIG. 1 ;  
         [0014]      FIG. 5  is an exemplary embodiment of internal circuitry within an L-Device;  
         [0015]      FIG. 6  is a detailed embodiment of the internal circuitry within the L-Device of  FIG. 5 ;  
         [0016]      FIG. 7  is a third exemplary embodiment of the L-Device of  FIG. 1 ;  
         [0017]      FIG. 8  is a first exemplary embodiment of a talking device (T-Device) of the hearing-impaired communication system of  FIG. 1 ;  
         [0018]      FIG. 9  is an exemplary embodiment of internal circuitry of a T-Device accompanied by an L-Device;  
         [0019]      FIG. 10  is a second exemplary embodiment of a hearing-impaired communication system;  
         [0020]      FIG. 11  is another embodiment of a stereophonic headset for the L-Device as shown in  FIG. 10 ;  
         [0021]      FIG. 12  is an embodiment of internal circuitry within the T-Device of  FIG. 10 ;  
         [0022]      FIG. 13  is an exemplary embodiment of a group charger for one or more L-Devices and/or T-Devices;  
         [0023]      FIG. 14  is a third exemplary embodiment of a hearing-impaired communication system;  
         [0024]      FIG. 15  is an exemplary embodiment of a T-Device with peripheral connectivity;  
         [0025]      FIG. 16  is a fourth exemplary embodiment of a hearing-impaired communication system deployed as an expandable fixed frequency or spread spectrum network;  
         [0026]      FIG. 17A  is an exemplary embodiment of internal circuitry within the T-Device of the hearing-impaired communication system of  FIGS. 16 ;  
         [0027]      FIG. 17B  is an exemplary embodiment of internal circuitry within the L-Device  1500  of the hearing-impaired communication system of  FIGS. 16 ;  
         [0028]      FIG. 18  is a fifth exemplary embodiment of a hearing-impaired communication system deployed as a designated call center;  
         [0029]      FIG. 19  is a sixth exemplary embodiment of a hearing impaired communication system;  
         [0030]      FIG. 20  is an exemplary embodiment of a built-in interconnect recoil mechanism situated within a L-Device or T-Device;  
         [0031]      FIG. 21  is an exemplary embodiment of an infrared based hearing-impaired communication system;  
         [0032]      FIG. 22  is an exemplary embodiment of a hearing-impaired communication system deploying an all-in-one earpiece; and  
         [0033]      FIG. 23  is an exemplary embodiment of a hearing-impaired communication system utilizing laser pointer activation of an IR detector of a T-Device.  
     
    
     DETAILED DESCRIPTION  
       [0034]     Various embodiments of the invention relate to a hearing-impaired communication system deploying an assisted listening device and one or more talking devices. The assisted listening device enables hearing-impaired persons to better comprehend speech conversations, especially in an environment having a high level of ambient noise such as a restaurant, theater, or any public meeting place. Examples of ambient noise sources include, but are not limited to the following: conversations by others in the background, equipment noise (e.g., heating, air conditioning, office equipment), road traffic or the like.  
         [0035]     In the following description, certain terminology is used to describe features of the invention. For instance, the term “device” is representative of hardware and/or software configured to perform one or more functions. An example of “hardware” includes, but is not limited or restricted to a collection of electronic circuitry such as tunable receivers, gain amplifiers, speakers, filters, signal converters or the like. Likewise, an example of “software” includes a series of executable instructions in the form of an application, an applet, or even a routine. The software may be stored in any type of machine readable medium such as a programmable electronic circuit, a semiconductor memory device such as volatile memory (e.g., random access memory, etc.) and/or non-volatile memory (e.g., any type of read-only memory “ROM”, flash memory), a floppy diskette, an optical disk (e.g., compact disk or digital video disc “DVD”), a hard drive disk, tape, or the like.  
         [0036]     Referring now to  FIG. 1 , a first exemplary embodiment of a hearing-impaired communication system  100  deployed as a spread spectrum wireless network is shown. Communication system  100  comprises an assisted listening device  110  (referred to as “L-Device”) and “N” talking devices  120   1 - 120   N , where N≧1 (referred to as “T-Device”).  
         [0037]     L-Device  110  may be configured to listen to all T-Devices  120   1 - 120   N  simultaneously with no cutouts. This implementation is a fully multiplexed scheme. It is contemplated, however, that L-Device  110  may be configured to listen to only one T-Device  120   1 , . . . , or  120   N  at a time. Each T-Device  120   1 - 120   N  is registered with L-Device  110  in its communication cell area. Such registration may be accomplished by T-Device providing a login code to L-Device  110 .  
         [0038]     In particular, during power-up of a T-Device (e.g., T-Device  120   1 , the registration process begins by generating a login code  130 , which may be a pseudo-random number or a random number. The login code  130  is transmitted in a broadcast fashion from T-Device  120   1  to any L-Devices in its general proximity. L-Device  110  receives the login code  130  and stores the login code  130  within volatile memory and/or non-volatile memory implemented within L-Device  110 . Thereafter, any audio communications from T-Device  120   1  to L-Device  110  are recognized and processed.  
         [0039]     Of course, although not shown, it is contemplated that L-Device  110  may initiate registration by broadcasting a registration message for receipt by all T-Devices  120   1 - 120   N  within its broadcast area. This may prompt T-Devices  120   1 - 120   N  to generate login codes and transmit these login codes to L-Device  110  via a registration response message.  
         [0040]     Referring now to  FIG. 2 , a first exemplary embodiment of L-Device  110  operating as a receiver is shown. Herein, according to one embodiment, L-Device  110  is assembled to resemble a cellular telephone, but with oversized, highly tactile input/output (I/O) controls to accommodate for lack of dexterity or vision normally found in the hearing-impaired demographic group. L-Device  110  comprises a body case  200  made of a semi-rigid material (e.g., hardened plastic, metal, etc.) and provides water and/or shock resistance in order to protect the inner circuitry from contaminants and adverse weather conditions. The body case  200  comprises a plurality of openings to allow a user visual or physical access to the I/O controls.  
         [0041]     For instance, as shown in  FIG. 2 , I/O controls  210  may protrude through prescribed openings in body case  200  to enable the user to adjust the functionality of L-Device  110 . Examples of I/O controls  210  may include, but are not limited or restricted to a power button  215  and volume control buttons  220  to adjust the volume and audio frequency ranges. This enables the listener to concentrate the incoming audio signal on user-specific audible frequency ranges.  
         [0042]     In addition, L-Device  110  further comprises an earpiece  225  that is connected to body case  200  via an interconnect  230  and input port  235 . Input port  235  may be an RJ-11 jack or other jack adapted for earpiece  225 . Interconnect  230  may be a wired or wireless (infrared or radio frequency) connection.  
         [0043]     L-Device  110  further comprises an optional low battery indicator  240  visible on a top surface of body case  200 . When L-Device  110  is in a low power state, battery indicator  240  is illuminated in order to signal the listener that the current power supply should be replaced or recharged. Of course, in lieu of battery indicator  240 , it is contemplated that a warning of a low battery condition may be accomplished through audio signals propagating through to earpiece  225  or an audible sound over a speaker (not shown) on L-Device  110 .  
         [0044]     Although not shown, a liquid crystal display may be implemented as an optional I/O control  210  in order to identify devices in communication with L-Device  110 .  
         [0045]     Referring now to  FIG. 3 , a perspective side view of L-Device  110  of  FIG. 2  is shown. L-Device  110  further comprises a removable power supply  300  that is disposable or rechargeable and a coupling mechanism  310  to maintain power supply  300  in a connected state. L-Device  110  is further adapted with a clip  320  that allows L-Device  110  to be coupled to a belt or waistband for placement under clothing for those users that want a discreet listening device. The oversized tactile I/O controls  210  would allow for adjustment to be made through clothing. It is contemplated that in lieu of clip  320 , a coupling mechanism may be deployed on a top surface of L-Device  110  in order to allow a cord or necklace to be inserted through the coupling mechanism so that the L-Device  110  may be worn around the user&#39;s neck.  
         [0046]     Referring now to  FIG. 4 , a second exemplary embodiment of L-Device  110  of  FIG. 1  is shown. Herein, for this embodiment, L-Device  110  comprises a microphone  400  positioned to allow a listener to better hear persons (without a T-Device) talking in close proximity. For instance, microphone  400  may be positioned along interconnect  230  and slightly angled from a forward facing direction in order to better hear audible speech from a person in close proximity to the listener.  
         [0047]     Alternatively, although not shown, microphone  400  may be positioned on an edge surface of casing  200  facing upward. This implementation enables microphone  400  to detect audio from persons situated above and directly in front of the listener. For instance, microphone  400  is positioned to better hear a waitress, a cashier or another person directly talking to the listener, even while the listener is engaged in communications.  
         [0048]     Referring now to  FIGS. 5 and 6 , an exemplary embodiment of internal circuitry  500  within L-Device  110  of  FIGS. 2 and 4  is shown. It is contemplated that the general architecture of L-Device  110  is equivalent to the architecture of any of T-Devices  120   1 , . . . , or  120   N , except for implementation of an earpiece or microphone connected to body case  200  via an interconnect and input port. It is contemplated, however, that T-Devices  120   1 , . . . , or  120   N  may be implemented with distinct architectures as shown in  FIG. 8 .  
         [0049]     In general, internal circuitry  500  comprises a feedback circuit  520 , a voice coder/decoder (codec)  530 , a baseband controller  540 , a radio frequency (RF) module  550  and an antenna  560 . Antenna  560  is designed to receive and transmit signals according to a predetermined frequency range. For instance, the signals can be within 2.1 to 2.5 Gigahertz (GHz) range. In essence, the combination of L-Devices and registered T-Devices that collectively form a BLUETOOTH® party line to exchange voice data over common channels of a wireless BLUETOOTH® Spread-Spectrum network.  
         [0050]     A headset  510  comprises an earpiece and/or microphone. When collectively implemented, both of these components are coupled to feedback circuit  520 , which provides local feedback from a pre-amplifier  522  to a summing amplifier  524 . This provides sufficient signal amplification and enables the user to listen to himself or herself talk at an appropriate gain level.  
         [0051]     Voice Codec  530  provides a pre-amplifier  531 , a band-pass filter  532  and a digitizer  533  in the transmit (TX) direction. The combination of components is responsible for digitizing an incoming analog signal received from microphone  400 . The digitized data is routed to storage memory (e.g., RX buffer  541 ) of baseband controller  540 . In the receive (RX) direction, however, a digital-to-analog converter (DAC)  534 , band-pass filter  535  and amplifier  536  are used to produce an analog signal representative of digital data processed by baseband controller  540 .  
         [0052]     Baseband controller  540  operates in a conventional manner. In general, a message generator  542  is executed by a processor core  543  (e.g., digital signal processor, general microprocessor, a micro-controller, etc.) to generate a message. The message is based on at least a portion of digitized audio data contained in RX buffer  541  and a selected communication protocol  544 . This message is transmitted based on a selected frequency set forth by frequency hop control  545 . An RF control circuit  546  provides control information for the clock generator/phased-lock loop (PPL) to cause RF module  550  to transmit information at the selected frequency assigned by frequency hop control  545 .  
         [0053]     As shown, a user interface  547  is in communication with processor core  543 , which is responsible for generating the wireless message as well as parsing data (by message parser  548 ) from a wireless message for transfer to voice codec  530  for conversion. User interface  547  includes I/O controls while memory  549  contains programs, login codes and the like.  
         [0054]     As further shown in  FIGS. 5 and 6 , RF module  550  is a conventional unit that provides RF data transmissions and RF data reception inclusive of filtering, amplification, and demodulation.  
         [0055]     Referring now to  FIG. 7 , a third embodiment of L-Device  110  of  FIG. 1  is shown. Herein, for this embodiment, L-Device  110  is implemented with a cutout switch  600  that will discontinue the routing of audio signals from the L-Device  110  into earpiece  225 . According to one embodiment of the invention, cutout switch  600  may be situated along interconnect  230 . Alternatively, it is contemplated that cutout switch  600  may be situated on a top surface of body case  200 , or on earpiece  225  itself.  
         [0056]     When cutout switch  600  is moved from a first position (as shown) to a second position, the audio signals received from L-Device  110  are not routed to earpiece  225 . Instead, audio signals associated with ambient noise recovered from microphone  400  are routed to earpiece  225 . As shown, microphone  400  is situated along interconnect  230 .  
         [0057]     Referring now to  FIG. 8 , a first exemplary embodiment of talking device (T-Device) of hearing-impaired communication system  100  is shown. For this embodiment, T-Device  700 , equivalent to T-Device  120   1  of  FIG. 1  for example, is deployed having a different construction from L-Device  110  of  FIG. 2 . More specifically, T-Device  700  comprises tactile controls  710  which may include, but is not limited or restricted to, a low battery indicator  720 , power  725  and a volume reset control  730  to adjust volume (gain) for an audio transmission. T-Device  700  further comprises an optional audio speaker  735 . Audio speaker  735  may be used to indicate to the user that the battery power level is low in lieu of or in addition to low battery indicator  720 .  
         [0058]     T-Device  700  further comprises an interconnect  740  attached to a microphone  745 . Interconnect  740  may be a wired or wireless connection between microphone  745  and circuitry internally situated within casing  750  of T-Device  700 .  
         [0059]     Referring now to  FIG. 9 , an exemplary embodiment of internal circuitry within T-Device  700  of  FIG. 8  and an accompanying L-Device, such as L-Device  110  of  FIG. 2  for example, is shown. T-Device  700  comprises microphone  745  that communicates with a codec  800  to convert the analog signals into digital data. The digital data is routed to a baseband controller  810  that produces RF messages. These RF messages are routed to an RF module  820  which, using frequency hop control and protocol, creates wireless packets  830  for transmission.  
         [0060]     L-Device  110  receives the wireless packets from RF module  900  and performs amplification, filtering and demodulation operations on information associated with the wireless packets. The resultant information is provided to a baseband controller  910 , which parses the information to recover the digital data. The digital data is routed to a codec  920 , which converts the digital data into analog signals that are routed to one or more earpieces  225 .  
         [0061]     Referring now to  FIG. 10 , a second exemplary embodiment of hearing-impaired communication system  100  is shown. For this embodiment, a talking device (T-Device)  1000  is substantially similar to T-Device  700  deployed within hearing-impaired communication system  100  of  FIG. 8  is shown. However, as one of tactile controls  1010 , T-Device  1000  further comprises a bias control  1020  to appropriately bias audio signals transmitted to a L-Device  1050 . L-Device  1050  is generally identical to L-Device  110  of  FIG. 2  except for a stereophonic headset  1060  adapted to L-Device  1050 .  
         [0062]     According to this embodiment, bias control  1020  is a user adjusted, three-position switch (not shown) that appropriately biases audio signals transmitted to L-Device  1050 . Bias control  1020  specifies the location of the listener (LEFT, CENTER, RIGHT) with respect to the talker. The CENTER position may be chosen as the default position, and the switch is returned to the center position after a disruption of power.  
         [0063]     More specifically, internal circuitry within T-Device  1000  produces a packet of audio data that includes a field that specifies the general position (00=LEFT, 01=FACING, 10=RIGHT) of the talker to the listener based on the setting of bias control  1020 . Thus, if the listener is facing the talker, but slightly to the right of the talker and bias control  1020  is set accordingly, the audio signals at the L-Device  1050  are biased so that audio signals routed to a right earpiece  1065  of headset  1060  is amplified more than audio signals routed to a left earpiece  1070  of L-Device  1050 .  
         [0064]     Of course, it is contemplated that other transmission techniques may be used to identify the position of the talker to the listener. For instance, bias control  1020  may be a slidable adjustment bar as shown. The relative position of the bar would indicate in what direction the listener is to the talker. Thus, when T-Device  1000  transmits audio data packets to L-Device  1050 , these packets include an 8-bit field to specify the general position (in code to denote left/right/center, degrees, etc.) from the talker. A conversion (e.g., 180 degrees minus degrees provided) may be needed to compute the location of the talker to the listener in order to bias right earpiece  1065  and/or left earpiece  1070  of headset  1060 .  
         [0065]     Moreover, in accordance with another embodiment of the invention, bias contol  1020  may be accomplished by an array of LEDs controlled by momentary switches instead of a positionable switch as described above.  
         [0066]     As shown in  FIG. 11 , it is contemplated that L-Device  1050  may deploy a stereophonic headset  1100  that comprises a microphone  1110  and a pair of earpieces  1120  and  1130 . This embodiment differs from the embodiment of  FIG. 10  in which headset excludes microphone  1110 .  
         [0067]     Referring to  FIG. 12 , an exemplary embodiment of internal circuitry within T-Device  1000  of  FIG. 10  is shown. For directional analysis, a dual-ended antenna accessory may be used to orient the user through analysis of signal time or delta phase to triangulate T-Device locations and bias the audio signal appropriately to the listener&#39;s earpieces. Alternatively a dual-ended antenna can be built in L-Device  1050  with the ability to analyze signal time or delta phase, triangulate the T-Device&#39;s location and bias audio as received by the listener&#39;s earpieces.  
         [0068]     Referring now to  FIG. 13 , an exemplary embodiment of a group charger  1200  for one or more L-Devices and/or T-Devices is shown. For this embodiment, each L-Device would feature an external recharging connector that enables the battery to be recharged. For instance, according to one embodiment, the external recharging connector would protrude from a bottom or side panel of the casing of the L-Device or T-Device. According to another embodiment, the external recharging connector would be implemented as a port (or female connector).  
         [0069]     As shown, group charger  1200  comprises a plurality of charge stations  1210 ,  1220  and  1230 , which are electrically coupled together. Upon inserting the plug of a power cord  1235  into a power source (e.g., Alternating Current “A/C” wall socket, cigarette lighter, etc.), power is supplied to a primary charge station  1210 . This enables a battery of any L-Device or T-Device (hereinafter referred to as an “L/T-Device”)  1240  placed in primary charge station  1210  to be charged.  
         [0070]     As shown, primary charge station  1210  comprises a cradle  1212  featuring an inner sidewall  1214 . A connector  1215  is positioned along inner sidewall  1214 . When L/T-Device  1240  is placed into cradle  1212 , connector  1215  comes into contact with the external recharging connector of L/T-Device  1240 . Primary charge station  1210  further comprises an indicator  1218  to indicate a charge level of the L/T-Device and an auxiliary connector  1216  positioned along a sidewall of cradle  1212  for electrically coupling a neighboring charge station  1220  to receive power from power cord  1225 .  
         [0071]     As shown, each of the secondary charge stations  1220  and  1230  differ from primary charge station  1210  because these stations  1210  and  1230  include two auxiliary connectors  1222  &amp;  1224  and  1232  &amp;  1234  at opposite sidewalls. Primary charge station  1210 , in contrast, features a single auxiliary connector  1216  since with power cord  1235  for coupling to a power source.  
         [0072]     It is contemplated that each of these charge stations  1210 ,  1220  and  1230  features an automatic shut-off to sense when a battery of an L/T Device is fully charged so that no overcharging damage is done to these batteries. Of course, in lieu of the serial recharging scheme as shown in  FIG. 12 , it is contemplated that each of these charge stations  1210 ,  1220  and  1230  may be adapted with separate power cords.  
         [0073]     Referring now to  FIG. 14 , a third exemplary embodiment of hearing-impaired communication system  100  is shown. For this embodiment, a talking device (T-Device)  1300  is identical to a listening device (L-Device) and is shown as a listening/talking (L/T) device  1300 . Each L/T device  1300  comprises a casing  1310  and a plurality of I/O controls  1320  as described in  FIG. 2  for example. One notable distinction, however, is that L/T device  1300  comprises a manual switch  1330  that can convert the L/T device  1300  into a L-Device or a T-Device. Separate types of headsets  1340  and  1350  adapted to the L/T device  1300  to operate as a T-Device or L-Device, respectively.  
         [0074]     Referring now to  FIG. 15 , an exemplary embodiment of a T-Device with peripheral connectivity is shown. T-Device  1400  comprises at least one audio port  1410  adapted to receive audio signals from a corresponding peripheral audio/video (A/V) unit  1420 . According to one embodiment of the invention, the audio port  1410  provides a secondary communication interface, separate from an input port for coupling with an interconnect having a microphone and/or earpiece, that receives an incoming audio signal and prepares for transmission to one or more L-Devices  1430 . Alternatively, however, audio port  1410  is the same input port for coupling to the interconnect having the microphone.  
         [0075]     As shown, audio signals are analog signals provided to T-Device  1400  from a peripheral A/V unit  1420  (e.g., television, radio, compact disk player, MP3 player, etc.) via an audio interconnect  1405 . The audio interconnect  1405  may be a cable adapted for coupling to audio port  1410 . Alternatively, audio interconnect may be air to receive an IR or RF signal from peripheral A/V unit  1420 . T-Device  1400  broadcasts an audio signal to all L-Devices in the broadcast range, which cause audio playback directly to an earpiece (not shown) of L-Device  1430 .  
         [0076]     Referring now to  FIG. 16 , a fourth exemplary embodiment of hearing-impaired communication system  100  deployed as an expandable spread spectrum or fixed frequency network is shown. For illustration purposes, however, a fixed frequency network implementation is described below. However, it is evident that the same configuration may be used as a spread-spectrum network in order to minimize the need to develop chips to handle multiple transmitters. Instead, one type of chip can be used in each added module, provided the received audio signals are mixed together.  
         [0077]     Herein, L-Device  1500  comprises a body case  1510  made of a semi-rigid material (e.g., hardened plastic, metal, etc.) and provides water and/or shock resistance in order to protect the inner circuitry from contaminants and adverse weather conditions. Body case  1510  comprises openings for a corresponding number of I/O controls  1520  to adjust the functionality of L-Device  1500 . Examples of I/O controls  1520  may include, but are not limited or restricted to a power control  1530 , a low-battery indictor  1535 , a pair of volume controls  1540  to adjust the volume, a pair of audio frequency controls  1545  to enable the listener to concentrate an incoming audio signal on user-specific audible frequency ranges.  
         [0078]     In addition, L-Device  1500  further comprises a headset  1550  having an interconnect  1555  that is configured for insertion into an input port  1560 . Input port  1560  protrudes from or is accessible within body case  1510 .  
         [0079]     Unlike prior embodiments, L-Device  1500  comprises a connector (not shown) located at a bottom sidewall  1512  of body case  1510 . According to one embodiment, the connector may be an edge connector (male or female), but other type of connectors may be used. An adapter cover  1565  is placed over the connector when no receiver modules are coupled to the connector.  
         [0080]     Each T-Device  1570   1 - 1570   M  is provided with a corresponding receiver module  1575   1 - 1575   M , which is adapted for coupling in series with each other and to the connector of L-Device  1500 . Each receiver module  1575   1 - 1575   M  may be programmed to transmit and receive signals over one of a plurality of communications channels. It is contemplated that each communication channel may correspond to a different prescribed frequency.  
         [0081]     According to one embodiment of the invention, receiver modules  1575   1 - 1575   M  are programmed automatically, based on their placement in relation to the connector of L-Device  1500 . For instance, receiver module  1570   1  may be set to a first frequency while receiver module  1570   N  may be set to an Nth frequency, which does not interfere with the first frequency. T-Device  1570   1 - 1570   M , however, may be programmed by the user selecting a communications channel based on placement at the T-Device  1500 .  
         [0082]     Referring now to  FIG. 17A , an exemplary embodiment of internal circuitry within T-Device  1570   1  of FIGS.  16  is shown. T-Device  1570   1  comprises an antenna  1600 , a RF module  1610 , a channel select logic  1620 , a codec  1630  and a microphone  1640 . Herein, microphone  1640  receives an analog signal and routes the analog signal to a codec  1630 . Codec  1630  amplifies, filters and digitizes the signal for transmission to RF module  1610 . RF module  1610  modulates the signal based on the channel value set for channel select logic  1620  by the user. For instance, the channel value may be set by turning of a knob, depression of one or more control buttons, etc.  
         [0083]     Referring now to  FIG. 17B , an exemplary embodiment of internal circuitry within L-Device  1500  of FIGS.  16  is shown. L-Device  1500  comprises an antenna  1700 , a RF module  1710 , channel select logic  1720 , a codec  1730 , a summing amplifier  1740  and a headset  1750 . Herein, antenna  1700  receives a wireless message and performs amplification, filtration and demodulation operations on information associated with the wireless message. Channel select logic  1720  controls demodulation of the received wireless message based on the channel value provided by channel select logic  1720 . Herein, channel select logic  1720  is assigned a first channel value (CH 1 ). Codec  1730  performs digital-to-analog conversion, which is amplified by summing amplifier  1740  to produce an audible sound at headset  1750 .  
         [0084]     In addition, a receiver module  1575   1  comprises a RF module  1760 , channel select logic  1762  and a codec  1764 , which collectively operate as described above. In particular, receiver module  1575   1  is adapted for coupling codec  1764  to summing amplifier  1740  and RF module  1760  to antenna  1700 . The same architecture is provided for coupling additional receiver modules, such as RF module  1770 , channel select logic  1772  and codec  1774  of receiver module  1575   2 .  
         [0085]     Based on the positioning of the receiver modules  1575   1  and  1575   2 , channel select values are assigned a second channel value (CH 2 , where CH 2  is not equal to CH 1 ) and a third channel value (CH 3 , where CH 3  is not equal to CH 2  or CH 1 ).  
         [0086]     Referring now to  FIG. 18 , a fifth exemplary embodiment of a hearing-impaired communication system  100  deployed as a designated call center is shown. Herein, L-Device  1800  and T-Devices  1810 , and  18102  can communicate through radio frequency signals over the cellular band by calling into a designated call center  1820 . Call center  1820  is established by a wireless carrier, which allocates call time at no cost to the user or at a substantially reduced rate.  
         [0087]     According to one embodiment, L-Device  1800  may be adapted as a receive-only cell phone with oversized controls, frequency control, ambient microphone, etc. made specifically for the hearing impaired. Ideally, calls made to a special toll-free conference number could only be heard by a registered L-Device, thus limiting abuse to the system. The owner of L-Device  1800  would be charged, if at all, by the total talked minutes.  
         [0088]     Referring to  FIG. 19 , a sixth exemplary embodiment of a hearing impaired communication system  100  is shown. Herein, L-Device  1910  and T-Devices  1920   1 ,  1920   2  and  1920   3  are hard-wired together over a common hub  1930 . Hub  1930  controls peer-to-peer routing of audio signals from each of T-Devices  1920   1 ,  1920   2  and  1920   3  to L-Device  1910 . It is contemplated, however, that hub  1930  may be implemented as a single table-top box into which microphones and earpieces are connected. The table-top box would be configured to control multicast routing of the audio signals.  
         [0089]     Other features of a L-Device or a T-Device include, but are not limited or restricted to the following: (1) a built-in manual or automatic interconnect rewinder as shown in  FIG. 20 ; (2) Infrared communications between L-Device and one or more T-Devices as shown in  FIG. 21 ; (3) fabrication of an all-in-one earpiece adapted with L-Device or T-Device functionality as shown in  FIG. 22 ; and (4) laser pointer activation of an IR detector of the T-Device. Upon detection of a laser beam or unidirectional beam of light (e.g., IR beam), the IR detector activates or deactivates the microphone associated with the T-Device. This enables the user to focus on a particular talker as shown in  FIG. 23 . For instance, detection of an IR beam by an IR detector of a first T-Device causes the first T-Device to be activated. However, in order to hear a second individual using the second T-Device, the second T-Device would be activated as well. Alternatively, if the user wants to exclusively hear the user of the second T-Device (not the user of the first T-Device), the user may deactivate the microphone of the first T-Device by again directing an IR beam to the IR detector of the first T-Device.  
         [0090]     In the foregoing description, the invention is described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the present invention. The specification and drawings are accordingly to be regarded in an illustrative rather than in a restrictive sense.