Patent Publication Number: US-11658693-B2

Title: Two-way communication system and method of use

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 16/280,839 filed Feb. 20, 2019, which is a continuation of U.S. patent application Ser. No. 15/702,083 filed Sep. 12, 2017 (now U.S. Pat. No. 10,348,350), which claims priority to U.S. Provisional Application No. 62/398,390 filed Sep. 22, 2016, each of which is herein incorporated by reference in its entirety for all purposes. 
    
    
     FIELD OF THE INVENTION 
     Systems, devices and methods for two-way communication are disclosed. More specifically, systems, devices and methods for two-way communication are disclosed that have a mouthpiece component positionable within a mouth of a user. 
     BACKGROUND OF THE INVENTION 
     Covert operations necessitate communication systems with very specific and stringent requirements. Such operations typically require clear two-way communications systems which are not visible or minimally visible to an outside observer, that allow for complete audio awareness of the environment, and which can be utilized in a less than overt manner. 
     Current technology has not been able to completely meet these requirements as existing systems invariably include some small visible component observable to a perceptive onlooker. Current communication systems also suffer from an inability to effectively communicate the user&#39;s speech when in very loud environments due to poor signal to noise ratio. 
     Accordingly, there is a need for a communication system that fully meets the stringent requirements of covert operations and allows for clear audio transmissions even in high noise situations. 
     BRIEF SUMMARY OF THE INVENTION 
     The present disclosure relates generally to two-way communication systems having a mouthpiece component positionable within a mouth of the user. 
     The communication system disclosed allows the operator or user to hear their environment by leaving their hearing unobstructed and thereby enables complete audio situational awareness by the operator. 
     Generally, one variation of a two-way communication system may comprise a mouthpiece component having a housing which is configured for temporary securement upon a tooth or teeth of a user, the housing having an integrated antenna with one or more loop coils arranged (e.g., symmetrically or asymmetrically) within the housing. An infrastructure communication device which is configured to transmit or receive signals from the mouthpiece component and communicate with a remote communication device may also be included, as well as a relay component in communication with the mouthpiece component and which is configured to interface between the mouthpiece component and the infrastructure communication device. 
     In another variation, the two-way communication system may also comprise a system control which is in communication with the relay component and which is also configured to wirelessly provide an input to the relay component. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings shown and described are exemplary embodiments and non-limiting. Like reference numerals indicate identical or functionally equivalent features throughout. 
         FIG.  1    shows a schematic representation of a variation of a two-way communication system having a mouthpiece component, a relay component, an infrastructure communication device, and/or a system control. 
         FIG.  2    shows a variation of a mouthpiece component having an integrated NFMI antenna/coil. 
         FIG.  3 A  shows a partial cross-sectional illustration of a variation of a MEMS-type microphone assembly securable within a user&#39;s mouth. 
         FIG.  3 B  shows a perspective assembly view of variation of the mouthpiece component of  FIG.  1    that is securable within the mouth and upon one or more teeth of a user. 
         FIGS.  4 A and  4 B  show schematic illustrations of variations of the two-way communication system of  FIG.  1    where the mouthpiece component communicates with the infrastructure communications device via the relay component. 
     
    
    
     DETAILED DESCRIPTION 
     Systems, devices and methods for two-way communication are disclosed that can provide reliable and/or clear incoming and/or outgoing communication. The systems, devices and methods disclosed can provide reliable and/or clear communication in any environment, for example, low noise environments, medium noise environments, high noise environments, or any combination thereof. The systems, devices and methods disclosed can be adjusted in real-time, manually or automatically, to advantageously function in one or multiple environments that have, for example, dynamic noise conditions. 
     The systems, devices and methods disclosed can be partially or completely visible or invisible to an outside observer when in use by an operator or user. For example, one or multiple components of the systems, devices and methods disclosed—including the entire system—can be partially or completely visible or invisible, for example, to another person, an image capturing system (e.g., a camera- or video-based surveillance system), or any combination thereof. 
     The communication systems disclosed can be non-invasive systems, invasive systems, non-implanted systems, implanted systems, or any combination thereof. For example, the communication systems disclosed can be non-invasive and non-implanted systems. 
     The communication systems disclosed can allow for clear two-way half-duplex and/or full-duplex communications. 
     The systems disclosed can allow the operator or user to hear their environment by leaving their hearing unobstructed and thereby enable complete audio situational awareness by the operator. With the addition of hearing protection, the same systems instantly convert into complete tactical and general purpose communication systems, functional in high noise environments. 
     One aspect of the systems disclosed is the use of an in-mouth communication device (also referred to as a mouthpiece component) utilizing bone conduction driven into the teeth for received audio, and an integrated microphone as part of the mouthpiece component. For example, the mouthpiece component can have one or multiple mouthpiece microphones. The mouthpiece microphone(s) can be attached to or integrated with the mouthpiece component. Using the in-mouth communication device, the operator may leave the ears completely open and unobstructed to enable the user to be situationally aware. Clear communications are possible while eliminating all cables and headsets. 
     The communication systems disclosed are particularly well suited for low-visibility applications as all parts of the system may either be hidden under clothes or are otherwise not visible to an external observer. For loud environments where in-ear or on-ear hearing protection is warranted or otherwise desirable, the same communication systems may be used as a general purpose and/or tactical communication system by incorporating hearing protection. This not only provides safety for the user, but also allows for reduced external noise competition for the user&#39;s attention, such that incoming audio communications may be heard and understood with more clarity. Furthermore, having the microphone embedded in the mouthpiece component enables extremely good noise shielding capabilities such that clear outgoing audio transmissions are possible even in loud environments (e.g., deafeningly loud environments). In cases where hearing protection is acceptable, the system may also be used as a general purpose communication system. 
     The system can have (a) a mouthpiece component  10 , (b) a relay component  12 , (c) an infrastructure communication device  14 , (d) system controls  16 , or any combination thereof. For example,  FIG.  1    illustrates that the system can have (a) a mouthpiece component  10 , (b) a relay component  12  and (c) an infrastructure communication device  14 . As another example,  FIG.  1    illustrates that the system can have (a) a mouthpiece component  10 , (b) a relay component  12 , (c) an infrastructure communication device  14  and (d) system controls  16 . The system controls  16  may interface with the relay component  12 , as shown in the schematic diagram of  FIG.  1   . 
     Variations of individual system components are detailed below, including different options for embodiments and particular design attributes. 
     Mouthpiece Component 
     The mouthpiece component  10  removably attaches or clamps onto or around the molars, e.g., upper back molars, of the operator or user U and allows for normal speech, eating, and drinking without impediment. Additionally, the mouthpiece component  10  may be temporarily secured to the user&#39;s tooth or teeth without having to alter the user&#39;s dentition in any way such that the user may simply remove the component  10  from the tooth or teeth when finished, leaving the dentition unaltered. When the mouthpiece component  10  is to be used again, it may be simply reinserted within the mouth and secured to the tooth or teeth again. The mouthpiece component  10  also utilizes bone-conduction technology by actuating one or more transducers  18  incorporated into the mouthpiece component  10  and vibrationally coupled to the teeth T to convey incoming audio to the user, as indicated by the vibrational conductance. The mouthpiece component  10  also integrates a microphone assembly  20  to capture the user&#39;s speech V for outgoing audio transmissions. The mouthpiece component  10  may also incorporate a transmitter and/or receiver such as a transceiver  22  which enables wireless communication  24  with the relay component  12  to receive and transmit audio data. 
     The mouthpiece component  10  may be comprised of a low-profile housing configured for temporary securement within the mouth and upon the tooth or teeth of the operator. This mouthpiece component  10  utilized may be described in further detail in any one of the following patent references: U.S. Pat. Nos. 7,664,277; 7,682,303; 7,724,911; 7,796,769; 7,801,319; 7,844,064; 7,844,070; 7,854,698; 7,876,906; 7,945,068; 7,974,845; 8,023,676; 8,150,075; 8,160,279; 8,170,242; 8,177,705; 8,224,013; 8,233,654; 8,254,611; 8,270,637; 8,270,638; 8,291,912; 8,295,506; 8,333,203; 8,358,792; 8,433,080; 8,433,082; 8,433,083; 8,503,930; 8,577,066; 8,585,575; 8,588,447; 8,649,535; 8,649,536; 8,649,543; 8,660,278; 8,712,077; 8,712,078; 8,795,172; 8,867,994; 9,113,262; 9,143,873; 9,185,485; 9,247,332. These patent references are incorporated herein by reference in their entirety and for any purpose herein. 
     The wireless link  24  between the mouthpiece  10  and relay component  12  is utilized in order to get audio data into and out of the mouth area may utilize any number of wireless data transmission protocols, e.g., near field magnetic induction (NFMI), radio frequency (RF) link such as BLUETOOTH®, body conduction, or acoustic signals at or above human hearing. Utilizing NFMI is generally preferable to RF due to reduced attenuation through body tissue and also due to a reduced electromagnetic far field profile. Regardless of wireless link implementation, the data can be encrypted to ensure security using, e.g., AES-256 or other encryption standards. 
     The mouthpiece component  10  can have an antenna (also referred to as a sensing mechanism) to receive signals/data (e.g., from the relay component  12 ). The sensing mechanism can be attached to or integrated with the mouthpiece component  10 . The sensing mechanism can desirably allow the mouthpiece component  10  to receive data without a wire and can be, for example, a transducer, electrode, or other sensing mechanism that can function as an antenna. For example, the mouthpiece component  10  can receive data via body conducted signals (such that the body is the sensing mechanism, for example, the body can be an electrode), via acoustic signals sent at or above human hearing to a piezo transducer, via electromagnetically with an RF antenna, via a magnetic field with a loop/coil antenna. For example, using NFMI for the wireless link means the mouthpiece  10  is utilizing an integrated NFMI antenna/coil  32 , as shown in  FIG.  2   . This may be completed through either a wire-wound ferrite core antenna or a wide loop option such as a larger loop coil  30 . Regardless of implementation, one design consideration is the ability of the mouthpiece component  10  to work similarly whether placed on the right or left upper molars, as different users may require different sides depending on dental anatomy. This means NFMI coil/antenna  32  placement preference is somewhere symmetric, such as along the bottom or top edge of the mouthpiece  10 . 
     The integrated microphone  20  capability in the mouthpiece component  10  may be implemented with either, e.g., a MEMS-type air microphone or a PVDF film type vibrational sensor, as described in further detail below. 
     For a MEMS type microphone assembly  40 , as shown in the partial cross-sectional illustration of  FIG.  3 A , the in-mouth sound pressure levels are high (e.g., up to ˜150 dBSPL) necessitating audio attenuation as part of the microphone assembly to prevent clipping and distortion. MEMS type microphones also typically utilize the presence of a small air cavity  42 , so this implementation may include a waterproof barrier  44  such as a tape or film as well as an attenuation element  46  such as a silicone disk, as part of the audio path to the air cavity  42  created for the microphone  48 . The air cavity  42  may be formed in part by a first substrate  50 , e.g., PCB defining an opening or channel  52  to the MEMS microphone  48 , and a second substrate  54 , e.g., housing structure formed from a material such as epoxy, which may form the sidewalls of the air cavity  42 . The attenuation element  46  may be mounted upon the second substrate  54  along with the barrier  44  positioned upon the attenuation element  46  and the second substrate  54 , as shown. The portion of the assembly  40  upon which the barrier  44  is positioned may be positioned adjacent to the outer surface of the mouthpiece component  10 , e.g., facing the palate of the user. 
     In order to handle the limited dynamic range of typical conventional MEMS microphones, the attenuation  46  added as part of the assembly  40  may be typically selected to still allow normal as well as low-voice speech levels, but enough attenuation such that loud talking or yelling will not be distorted, e.g., attenuation on the order of −30 dB is sufficient to prevent audio clipping. A good system level compromise will allow some distortion and clipping of sound pressure levels corresponding to the user screaming. This ensures the lower-end of the dynamic range will accept light talking down to whisper level audio. 
     The placement of the audio port  64  for a MEMS microphone  48  is desirably placed on a surface of the mouthpiece  10  which faces the palate, as this position is stable, is exposed to the highest speech sound levels, and does not get impacted by tongue and cheek movements during speech which can give rise to undesired audio artifacts. A tooth-facing position is also an acceptable alternative. It should be noted that due to an in-mouth MEMS microphone placement, the user&#39;s speech is loud so the signal-to-noise ratio (SNR) is large. External noise sources are dampened not only by the user&#39;s own cheeks and dental anatomy, but by the attenuation of the microphone assembly  40 . This allows for clear recorded voice audio, down to whisper level, even in very loud external noise environments. 
     The microphone capability of the mouthpiece may also be implemented using, e.g., a polyvinylidene fluoride or polyvinylidene difluoride (PVDF) film vibrational sensor. This technique utilizes amplification circuitry to process the small signals output from the piezo-electric film material, as well as electrical shielding techniques to help reduce noise. The PVDF film material may be placed on an interior section of the mouthpiece enclosure, to pick up vibrations of the enclosure itself, as long as the film is backed either by air or a flexible material. Benefits of the PVDF film implementation may include a reduced implementation volume as well as inherently good noise shielding from the external environment as air-based incoming sound impinging on the user does not give rise to large physical vibrations inside the user&#39;s mouth. Both microphone implementation methods, therefore, provide the ability to issue clear audio transmissions with good SNR even in cases where the user is unable to hear themselves talk due to environmental noise conditions. 
     The mouthpiece  10  desirably provides a physical vibration drive onto the teeth to implement the bone conduction audio path previously described. This may be accomplished by using a piezo-electric material, e.g., with a piston-type interface to translate the small vibrations onto the surface of the tooth or teeth. Previous disclosures have detailed this interface and potential architecture options, as incorporated herein above, including simple beam with weights to reduce the mechanical resonant frequency, as well as a cantilever type configuration to again help lower the resonant frequency and also reduce the mechanical source impedance of the device to better translate power to the tooth. Additionally or alternatively, the mouthpiece  10  can have two actuators, located on either side of the mouth (e.g., both located on the left or right side of the mouth, or one located on the left side and one located on the right side), and provide “3D” or “directional” audio by slight timing differences/phasing between the two actuators. This can help to tell the difference between incoming audio from different radio sources in the case where the relay component  12  is connected to multiple infrastructure communication devices  14  at once. Additionally or alternatively, the mouthpiece component can be designed such that one actuator (e.g., a first actuator) can be on a left side of the mouth and such that one actuator (e.g., a second actuator) can be on a right side of the mouth. Additionally or alternatively, the mouthpiece component  10  can have multiple actuators located on one or both sides of the mouth (e.g., one actuator on a left side and two actuators on a right side). 
     The mouthpiece component  10  can be powered without a battery source. For example, the mouthpiece component  10  can be powered through the oscillations of a magnetic field as a means of live power transfer. For example, the mouthpiece component  10  can be powered with a wireless power transfer system. In this way, the mouthpiece component  10  can be a “passive” component without a battery source. Alternatively or additionally, the mouthpiece component  10  can have an internal power source. This may either include a replaceable battery or integrated rechargeable battery. The use of a rechargeable battery may allow the system to remain sealed and waterproofed without having to incorporate a separate waterproof compartment to allow for battery replacement. The method of recharging the internal battery may be either contact charging through exposed metal contact pins on the mouthpiece external surface, or through a wireless inductive or resonant charging technique. The wireless methods may allow for complete mouthpiece component sealing and less risk of leaks and fluid ingress. In order to make the inductive charging work for a device small enough to be worn in the mouth, certain design aspects may include creating a very tight coupling between the charger transmit coil and the mouthpiece receive coil. Distance between those coils are desirably minimized through design, and ferrite sheet backing material used to help reduce heat and again increase the coupling coefficient. The device is relatively small enough that a custom transmit coil made to match and align with the mouthpiece recharge coil is advantageous. 
     The mouthpiece component  10  enclosure itself is desirably physically small but also very strong in order to ensure the internal components and battery are protected and safe even under potential bite-force of the user. To this end, the circuitry and battery may be encapsulated, e.g., with epoxy  54 , as part of the design such that all of the potentially hazardous materials are completely encased in a bio-compatible material such as that used in pacemaker headers. A typical implementation would include the epoxy filling  54  of a bio-compatible plastic enclosure, but to reduce size even further the plastic enclosure may be skipped altogether and the epoxy  54  may be molded around the electronics in the desired component shape. This allows for tight control and small dimensions for the gap to a recharge coil, for instance. It also allows for the ability to create a small MEMS microphone air cavity  42  through the use of core pins during the epoxy mold process. This air cavity  42  may then be integrated with the aforementioned acoustic attenuation components. Top or bottom port MEMS microphones can be used along with this method. 
     Lastly, the mouthpiece component  10  may be clamped to the user&#39;s tooth or teeth, e.g., upper back molars, using some clamping and fit mechanism, as illustrated in the perspective view of the mouthpiece component  60  shown in  FIG.  3 B . This is best done by having some portion of the mouthpiece be user-specific, and custom to their dental anatomy, to ensure the best clamp/retaining force, and to optimize comfort. The customized-portion of the mouthpiece may either be integrated into the mouthpiece assembly  10  as a single custom piece, or it may be separable such that the dental-adapter to the individual may be constructed separately than the mouthpiece electronics package, and the two parts mate together to create the overall mouthpiece system component. 
     As shown, the mouthpiece component  60  may include the microphone assembly housing  62  having a size configured for unobtrusively positioning within the user&#39;s mouth for extended periods of time, e.g., along the lingual or buccal surface(s) of one or more teeth, placed against the palate. The housing  62  may have a length of, e.g., 25 mm, and a height of, e.g., 15 mm, with the audio port  64  for a MEMS microphone (contained within the housing  62 ) defined along the side of the housing  62 . The audio port  64  may be defined along the side of the housing  62  facing towards the palate when the component  60  is secured within the mouth, but in other variations, the audio port  64  may be defined at other locations such that it faces the teeth (either lingual or buccal surface) or the inner surface of the user&#39;s cheek. 
     In either case, the housing  62  may have a first portion of a conformable securement member  66 , e.g., dental acrylic, attached along the side of the housing while a second portion of the conformable securement member  66  may define an interface  68  which is conformable to the patient&#39;s underlying dentition. Alternatively, the second portion of the conformable securement member  66  may instead be formed into a simplified configuration which is atraumatic and positionable against a variety of dentition. An actuator housing  70  having a contact portion  72  for placement against the surface(s) of the one or more teeth (e.g., within the interproximal space between teeth) may be positioned in apposition to the interface  68  such that a receiving region  78  is formed between the two within which the one or more teeth may be positioned. 
     The actuator housing  70  may contain at least some of the electronics and one or more actuators which are configured to vibrate according to the signals received for transmitting auditory signals via vibrational conductance into the underlying surfaces of the one or more teeth in contact with the contact portion  72 . The actuator housing  70  and contact portion  72  may be maintained in its position relative to the housing  62  via a connecting member  74 , e.g., hypotube, which has an embedded portion  76  secured or otherwise attached within or to conformable securement member  66 . The connecting member  74  may be flexible enough to allow the actuator housing  70  and assembly housing  62  to temporarily flex away from one another during securement of the assembly  60  upon the user&#39;s dentition as the tooth or teeth are positioned within the receiving region  78 . 
     Yet when suitably positioned, the actuator housing  70  and contact portion  72  may clamp or otherwise become secured against the tooth or teeth, e.g., via an interference fit between the assembly  60  and the surfaces of the user&#39;s tooth or teeth. The connecting member  74  may be positioned, e.g., to extend proximally around the distal surface (i.e., opposite of the mesial surface) of the last positioned molar (i.e., third molar) so that the occlusal surfaces of the tooth or teeth remain free and unobstructed by the assembly  60 . 
     Relay Component 
     A second component of the communication system  80  may include the relay component where the relay component  12  of the communication system functions as an interface between the infrastructure communications device  14  (e.g., cell phone, walkie-talkie radios, intercom device, etc.) and the mouthpiece component  10 , as shown in the illustrative drawing of  FIG.  4 A . The relay component  12  may convert the audio available at the infrastructure communication device into a wireless signal expected by the mouthpiece component  10 , and vice-versa. 
     Depending on the wireless link type chosen between the mouthpiece component  10  and relay component  12 , possible wireless links  84  between the mouthpiece component  10  and relay component  12  may include, e.g., Near Field Magnetic Induction (NFMI), body-conduction/body-network, a combination of these, or RF such as Bluetooth®. One link type is NFMI which enjoys relatively little attenuation through body tissue, and also has a low electromagnetic propagation for a low RF profile. For this implementation, the relay component  12  incorporates an inductive coil component which may be incorporated into the communications system. One variation may incorporate an antenna  82  configured as, e.g., a neck-loop or a patch-antenna. The direction of the magnetic field lines in relation to the mouthpiece antenna/coil, as illustrated in  FIG.  2    above, may be taken into account when determining a location of the relay component NFMI antenna  82 . For instance, neck-loop configurations may use a bolo-type cinching mechanism to tighten the loop around the neck and further has the benefit of changing the direction of the magnetic field lines, e.g., from forward tilting to more straight up towards the head which can give tighter coupling to the mouthpiece component  10  and a more robust wireless link. Loops may also be worn around the head of the user U and may be beneficial from this standpoint. Such loops may be integrated into any number of head-worn accessories, e.g., helmets, hats, etc. Neck-loops may also incorporate, e.g., a break-away connector feature for safety purposes. 
     Regardless of placement, it is advantageous to ensure there is some amount of separation between the antenna wire  82  and the human body (even if a few millimeters of separation), in order to preserve a higher Q (quality factor) of the antenna  82 . In some variations, patch coils may be worn in various places but to ensure optimal field line position, the back of the neck or back of the head may work best. If NFMI is used at a fixed frequency, the magnetic field strength may be reduced in order to avoid user-to-user interference when multiple communication systems are worn in close proximity. Otherwise, time-sharing the bandwidth or utilizing dedicated frequency channels may be handled. 
     The wireless link  84  to the mouthpiece component  10  may be encrypted to ensure secure communications, e.g., using AES-256 or another chosen encryption algorithm. If unique encryption key-exchange is required, this may be achieved through an exchange over NFC or other close proximity-based method, between the mouthpiece component  10  and desired relay component  12 , prior to use. 
     While the physical implementation of the relay component  12  may be a separate electronics enclosure with attached wireless link antenna to communicate with the mouthpiece component  10 , other variations may have the relay component  12  physically mate and/or integrate with the infrastructure communication device  14  (described in further detail below). If the relay component  12  is a device physically separate from the infrastructure communication device  14 , then a link  86  (either wired or wireless) may be established between the relay component  12  and infrastructure communication device  14 . Since both devices would be outside of the body of the user, there are less restrictions on this link implementation, and protocols such as Bluetooth® or other RF communications may be used. 
     In the variation of the communication system  90  illustrated in  FIG.  4 B , the relay component  94  may be integrated into the infrastructure component  96 , e.g., directly integrated, integrated into a case or housing such as a cell phone case, etc., such that a single integrated infrastructure communications device  92  may be used to communicate  98  wirelessly with the mouthpiece component  10 . 
     Regardless of the specific chosen placement and implementation of the relay component  12 , from a system level the relay component  12  may incorporate one or more processors for implementing digital signal processing (DSP) in order to minimize power consumption at the mouthpiece component  10 . For a half-duplex system the DSP is not as critical as there is no feedback issue, but even basic filtering may be done at this point to save power. 
     Moreover, the relay component  12  may incorporate one or more user interface features which allow for the user U to interface with the system settings and modes, e.g., a push-to-talk (PTT) button for half-duplex audio communications and/or full-duplex communications (or to switch between half- and full-duplex communications), receive volume controls, etc. These controls may be integrated into the physical implementation of the relay component  12 , or they may be separated out into a separate remote control with a new data link, such as Bluetooth® (e.g., Bluetooth® low-energy (BLE)), other RF link, an NFMI link, or simply a wired connection. An NFMI link which connects the relay component  12  with the remote control can desirably allow for better performance under water. Where an NFMI link is used with both the mouthpiece component  10  and the relay component  12 , the mouthpiece and relay component NFMI links can each operate at a different frequency from one another, or the NFMI link for each can be time-shared/coordinated with each other such that a different frequency is not needed. For a wireless remote control, the implementation may be something physically similar to, e.g., a key-fob, to be worn in the pocket for easy concealment. More advanced devices could also provide system status information. Information sent to a smart watch would be one way to accomplish this. 
     The relay component  12  may either obtain power directly from the infrastructure communication device (if available), or be battery powered and require either battery replacements or recharge. An integrated rechargeable battery may be implemented for size reduction reasons. In order to recharge the device, one variation may utilize a break-away type feature of an NFMI neck-loop to access recharge contact pins, which are typically inaccessible during operation. In order to save power, when implementing a half-duplex system over a full-duplex infrastructure such as a cell phone, an audio-level sensor may be used to notify the system when it is able to transition into an idle mode (not actively transmitting or receiving audio). 
     Infrastructure Communication Device 
     As mentioned above, the communication system described may be used to interface with another infrastructure communication device such as a cell phone, radio, intercom device, etc. For wired connections to the relay component  12 , audio in/out signals may be available, while wireless links such as Bluetooth® (e.g., Bluetooth® low-energy (BLE), other RF links, or NFMI links are also an option to use two-way audio data to shuttle between the relay component  12  and the infrastructure communication device  14 . NFMI links can advantageously allow for under water usage. Where an NFMI link is used with both the relay component  12  and the infrastructure communication device  14 , the relay component and infrastructure communication device NFMI links can each operate at a different frequency from one another, or the NFMI link for each can be time-shared/coordinated with each other such that a different frequency is not needed. If the device supports voice activated commands, these may be engaged using the audio over the described communication system components. 
     Additionally and/or optionally, the relay component  12  may also be implemented such that there are links to two or more separate infrastructure communication devices worn by the same user simultaneously (such as two radios used in tactical operations, to two different teams). Incoming audio is typically designated in current dual-communication systems by driving audio to either the right or left ear in a headset. For a system with a single mouthpiece, a pre-audio notification may be used to alert the user as to which device is the source of incoming audio. If a mouthpiece includes teeth-drive contact points on both the right and left sides of the mouth, audio may be phased to these drive points such that the perceived audio is coming from the right or left side. 
     All references including patent applications and publications cited herein are incorporated herein by reference in their entirety and for all purposes to the same extent as if each individual publication or patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety for all purposes. Many modifications and variations of this invention can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. 
     The specific embodiments described herein are offered by way of example only. Moreover, such devices and methods may be applied to other sites within the body. Modification of the above-described assemblies and methods for carrying out the invention, combinations between different variations as practicable, and variations of aspects of the invention that are obvious to those of skill in the art are intended to be within the scope of the claims.