JPH02299330A - Light wavelength communication equipment and method for utilizing the same - Google Patents

Abstract

PURPOSE: To prevent the occurrence of sensitivity suppression without interference in optical wave communication by matching the emitter wavelength to the frequency of a base station receiver and matching the frequency of the receptor to the emitter of a base station. CONSTITUTION: A remote device 414 includes an emitter 433, a receptor 435, a remote voltage controlled oscillator 496, a frequency control circuit 497, and a pair of high Q preamplifiers 410 and 420. The wavelength of the remote device emitter 433 doesn't match the carrier wavelength of the remote device receptor 435. However, the emitter wavelength matches the frequency of the base station receiver 430, and consequently, communication between a base station 412 and remote devices 412 and 416 is possible. In the same manner, the wavelength of the remote device receptor 435 matches the wavelength of a base station emitter 428, and consequently, communication between all remote devices and the base station 412 is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention generally relates to an optical wavelength communication device and a method of utilizing the same, and specifically, it is preferable to operate with an infrared wavelength carrier wave. The present invention relates to such an optical communication system.

Summary of the Prior Art and Problems to be Solved by the Invention Optical wavelength communication systems are highly desirable for use in many different applications. For example, such a system could be used to replace radio frequency systems, such as those used in fast food restaurants, but
This is because optical wavelength systems do not require special government approval and are more tolerant of noise interference.

For example, a short-range, optical wavelength carrier communication system is disclosed in co-pending application S.N. 07/176, 939, filed April 4, 1988 and assigned to the same attorney as the present application. In this concurrent application, an optical wavelength communication system enables full duplex communication between two or more transceivers. In this regard, both transceivers can simultaneously communicate with each other via a single optical wavelength carrier signal.

A single optical wavelength carrier is utilized and this carrier is shared on a time division multiplexed basis to avoid sensitivity problems where the outgoing signal may interfere with the incoming signal. Such wavelength carrier schemes are very useful for many applications and sb
However, it would be highly desirable to have a wavelength communication system that does not utilize a time division multiplexing configuration. In this regard, a full duplex optical wavelength carrier communication system that does not require complex time division multiplex synchronization circuitry would be highly desirable.

Therefore, it would be highly desirable to have a full-duplex, optical wavelength carrier system that operates with either single or multiple wavelength carriers without the need for time division multiplexing synchronization circuitry.

Such a device would be very effective and as sensitive as time division multiplexing. In this regard,
Such a scheme must be constructed in such a way that the outgoing signal is not interfered with by the incoming signal, thus resulting in unnecessary and undesirable insensitivity.

Also, such a system should be relatively inexpensive to manufacture.

C. Embodiments The above and other objects and features of this invention, and the manner in which they are obtained, as well as the invention itself, can be understood by referring to the following description of embodiments of the invention, taken in conjunction with the accompanying drawings. shi, will be best understood.

In particular, FIG. 1 shows a wireless infrared full duplex communication device 10 constructed in accordance with the present invention and suitable for use as an intercommunication system. Accordingly, device 10 is a single wavelength carrier device that can be utilized in commercial establishments, such as, for example, fast food drive-through restaurants or similar establishments.

Although a preferred form of the present invention is designed for use in audible communications in fast food restaurants,
It will be apparent to those skilled in the art that the principles of the invention may be utilized for other applications as well. for example,
The information being communicated can include data, voice, combinations thereof, and others. Additionally, the wireless communication scheme of the present invention can be utilized in other environments, such as restaurants where food is consumed on-premises and orders are taken from consumers waiting in line. Furthermore, the wireless communication system of this invention is
Transportable or portable computers or terminals can be moved from place to place and used in production department settings where data and other information can be entered. Additionally, the wireless communication system of this invention can be used in office settings where computers and other such equipment are arranged in a web and it is desired to interconnect them without the need for cables. Then a tortoise is formed.

Device 10 generally includes a relay base station or device 12 that interconnects a set of similar remote devices or stations, such as remote devices 14 and 16, in optical communications. Although only two remote devices 14 and 16 are shown for illustrative purposes, it will be apparent to those skilled in the art that many more remote devices (not shown) may also be utilized. The remote device is adapted to be handled by an attendant at a 7-star restaurant. This staff member has
This typically includes those who take orders and those who prepare food.

Speaker 18, vehicle detector 19 and microphone 20
is located at a remote customer location 22 where a customer sitting in a car (not shown) can place an order by speaking into a microphone 20. Speaker 1
8, the detector 19 and the microphone 20 are connected to the base station 12 by respective electrical cables 24, 25 and 26. Although speaker 18 and microphone 20 are shown as separate devices in the preferred embodiment,
It should be understood that a single speaker/microphone such as that disclosed in U.S. Pat. No. 498Z245 may be utilized in place of the separation device.

A portable foot switch 29 placed inside the restaurant can also be connected to the base station by cable 27 so that restaurant attendants can freely activate their remote devices by simply stepping on the switch 29. We are making it possible to do so. The base station also has engineering. A transmitter 28 and a receiver 30 are included. The remote devices also each include an emitter and a receptor. For example, remote device 14 includes emitter 33 and receiver 35, and remote device 16 includes emitter 57 and receptor 39. As shown in FIG. 1, the emitter and receiver communicate with each other at an optical carrier wavelength, preferably at a wavelength of 880 nm.

(g) Single-light wavelength multiplexing system Next, the operation of the device 10 will be discussed with reference to FIGS. 2 and 3. Apparatus 10 utilizes a single optical wavelength designated λ0 to establish a full duplex communication link between base station 12 and all of the remote devices, such as remote devices 14 and 16. The device still uses identification techniques to achieve full duplex transmission as will become clearer in more detail below. As will be apparent to those skilled in the art, a single communication channel is provided for each remote device,
and remote customer locations, whereby each channel is assigned a discrete wavelength and/or electrically selective preamplifier combination to achieve the infrared separation necessary for full-duplex transmission.

1. General Operation Turning now to the communication path between the customer location 22 and a remote device, when a customer drives to the remote customer location 22 (not shown)
I think I'll get on board. When a vehicle is located opposite customer location 22 , vehicle detector circuit 19 includes a vehicle sensor (not shown) activated by the vehicle and thus generates a signal that connects cable 25 . is transmitted to the base station 12 via the base station 12. This signal is then utilized to generate an audio signal, informing all remote devices of the customer's late night. The vehicle detection circuit 19 is a normal one,
For example, model 3 manufactured and sold by Indicator Control.
630314 or model 93501 sold by Detector Systems. If a customer vehicle is present at the remote customer location 22, the vehicle detection circuit generates an authorization signal. The customer verbally issues an order or message via microphone 20. This audible message is communicated electrically via cable 26 to base station 12 where it is modulated and optically transmitted to all remote devices.

Remote devices such as remote devices 14 and 16 are generally equivalent to each other, and therefore only device 14 will be described in detail with respect to FIG. 3 below. The optical message is detected by remote unit 14, where it is demodulated into an audible signal.

2 Base Device As shown in FIG. 2, the base station 12 includes an audio processing speaker relay circuit 40 and a summing amplifier 41,
The incoming audio signal from microphone 20 as well as the authorization signal from vehicle detector 19 is processed and amplified. A base station voltage controlled oscillator 43, hereinafter referred to as base VCO, modulates the incoming audio signal onto one of two predetermined subcarrier frequencies, designated fl and f2 KHz, respectively.

The base VCO 45 is controlled by a vCO frequency control circuit 44, which allows the base station VCO 43 to adjust its predetermined subcarrier frequency to two discrete frequency values f1.
and f! It can be changed between. The operation of VCO frequency control circuit 44 will be described in detail below.

As best seen in FIGS. 1 and 2, base station 12
Attached via a cable 27 is a portable footswitch 29, such as, for example, the footswitch available on the market from Control International under the designation model +862-1990-02. foot switch 2
The action of 9 is that the user activates the footswitch 29 and that the remote device 14's microphone 94
The ability to communicate with a customer at a customer location 22 by conveying verbal messages through a microphone at a designated remote station. In this regard, when footswitch 29 is activated (depressed), base station 12 modulates the audible signal to subcarrier frequency f.

Conversely, if the foot switch 29 is not activated,
The base station modulates the audio signal onto subcarrier frequency f1.

The foot switch 29 operates in communication with a foot switch control switch 90C disposed in the control module 90. The operation of the foot switch 29 by the control switch 90C will be explained in detail below.

To describe the communication path between the customer location (microphone 20) and the remote device via the base station 12, this mode of communication is referred to below as the "BASE MENU/PAGEJ" mode. MEN
In the tT/PAGE mode, the audible signal generated by the customer via microphone 20 is modulated onto a subcarrier frequency designated fl. This modulated signal is then transmitted at a single optical wavelength λ0, which is common to base station 12 and all remote units, such as remote units 14 and 16.

A transmit enable gate, shown as XMT gate 47, controls the output of base station VCO 45 via logic gate 45. Logic gate 45 controls or enables XMT gate 47 only if certain valid conditions exist, as will be explained in more detail below. Accordingly, the modulated audio signal at subcarrier frequency f1 is selectively allowed to be transmitted only if logic gate 45 receives a valid transmission condition at its input, as will be explained in more detail below. Ru.

The LED driver, ie, the light emitter driver circuit 49, has its input connected to the XMT gate 47 and its output connected to the light emitting optical antenna 28. antenna or emitter 2
8 transmits the outgoing signal at a single wavelength λ0 to all remote units.

The LED driver 49 and optical antenna 28 are conventional and well known to those skilled in the art. Thus, the single carrier wavelength signal λ0 radiated or emitted by the XMT antenna 28 is received by the receivers of all remote devices, such as the receiver light-receiving optical antenna 35 of the device 14, for example.

To isolate the base station's receiver photoreceptive optical antenna 30 from the infrared transmission signal being transmitted by its emitter 28, the base station 12 includes a pair of high-Q preamplifiers connected to the base station receiver 30. Circuits 70 and 80 are included. High-Q preamplifier circuits 70 and 80 and designated MENU and PAGE, respectively, transmit only those signals modulated to the subcarrier frequency being transmitted by the remote device to their respective outputs for demodulation purposes. let Therefore, MENU and PAGE circuits 70 and 80
converts the received signals from light wave modulated signals to radio frequency modulated signals and causes only those signals having subcarrier frequencies generated by remote devices, such as remote devices 14 and 16, to be transmitted.

Next, the vehicle detection circuit 19 will be considered in more detail with reference to FIG. Customer car at customer location 22 (not shown)
Whenever there is a vehicle detector 19 generates a grant signal, which is transmitted via cable 25 to the base station. Cable 25 connects to audio processing speaker relay circuit 40 and logic gate 45.

Therefore, if detector 19 generates its enable signal, the output of logic gate 45 will not be true, thereby enabling base station 12 to pass the outgoing audible signal through its XMT gate 47 to emitter 28. to all remote devices via.

Tone generator 40F of audio processing speaker relay circuit 40 in response to the enable signal generated by vehicle detector 19
is activated, allowing the presence of the customer's vehicle to cause the tone generator 40 to generate a low level warning (beeping) signal, which is then transmitted to all remote devices. In this manner, the customer's vehicle at the remote customer location 22 is simultaneously detected by all remote devices and brought to the attention of the restaurant attendant.

Next, referring to FIG. 8, the audio processing speaker relay circuit 4
Considering 0 in more detail, circuit 40 has three input paths. i.e. remote customer location microphones 20 to 2
Input path indicated by OA and vehicle detection device 19 to 25A
and the MENU squelch amplifier 4.
The input paths designated 40J are derived from 0I and are discussed in more detail below.

Therefore, the audio processing speaker relay circuit 40 is connected to the input path 20A.
Let's consider this in detail. The input signal received at input 2OA is generated from a remote customer location microphone 20. This signal is considered a loud voice signal from the customer and is read back to the remote device.

As best seen in FIG. 8, the large signal from microphone 20 is passed through speaker relay 40A to connector 20.
It is coupled to the incoming contact 40Al via A. The output of speaker relay 40A is connected to the input of high-pass filter 40B. High pass filter 40B improves the frequency response of the signal in input path 20A.

The output signal from high pass filter 40B is then passed through limiter 40
C, and its output is given to a summing amplifier 40D. The output of summing amplifier 40D drives compressor circuit 40E, the output of which is connected to adder circuit 41.

Next, the second human power applied to the speaker relay circuit 40A will be considered in more detail. This input is connected from the output of amplifier 401, as shown by line 40J. The output signal of amplifier 40I is an audible signal received from a remote station, which is to be transmitted to remote customer location speaker 18. Therefore, whenever a ratio signal is received by speaker relay circuit 40A, it switches from its human contact position aoAl to output contact position 40A2, thus transmitting the output audible signal to speaker 1 via line 18A.
Combines with 8. Incoming contact position 40A1 and outgoing contact position 40A
Since the electrical path between base station 12 and base station 2 is separate, the ratio signal is not transmitted to high-pass filter 40B and therefore is not retransmitted by base station 12.

Next, the input path 2 to the audio processing speaker relay circuit 40
5A, the input signal received at input 25A is the authorization signal generated by vehicle detection device 19. This signal is connected to the input of tone generator 40F, which generates a low level warning tone signal. The output of tone generator 40F is coupled to the input of summing amplifier 40D.

Summing amplifier 40D transmits the alarm signal to adder 41.

The output of adder 41 drives base station VCO 43, which transmits this signal to the selected subcarrier frequency flh or f!
modulates to. This modulated signal then passes through an XMT gate 47 enabled by gate 45. Accordingly, a periodic audible alert signal is transmitted by the base station to all remote devices. In this way, all remote station personnel can be made aware of the presence of the customer's vehicle at the remote customer location 22.

Next, referring to FIG. 8, the audio processing speaker relay circuit 40
Consider input path 78A in detail.

The signal received from amplifier 40I is derived from MENU squelch circuit 78. As best seen in FIGS. 2 and 8, the output of menu squelch circuit 78 is
It is coupled to low pass filter 40G, as shown by line 78A. For signal conditioning, the output of low pass filter 40G drives an expansion circuit 40H, the output of which is then connected to the input of amplifier 40I.

Next, the vCO frequency control circuit 44 will be considered in detail with reference to FIG. The vCO frequency control circuit 44 controls the frequency at which the base equipment voltage controlled oscillator 43 operates. More specifically, the VCO frequency control circuit 44 controls the base equipment voltage controlled oscillator 43 to adjust its predetermined subcarrier frequencies to f and f.
2, allowing the frequency to vary between two discrete frequency values, denoted by 2. Subcarrier frequency f, to f2
The purpose of changing to is explained in more detail below.

■The CO frequency control circuit 44 includes a pair of tuning circuits 4 that establish subcarrier frequency component signals f1 and f, respectively.
4A and 44B are included. As shown in FIG. 4, when foot switch 29 is turned off or disabled, the output of tuned circuit 44A is
join to. When the footswitch 29 is activated or turned on, the tuned circuit 44]3 is activated and the output of the f2 tuned circuit 44B is coupled to the base 700 circuit 43.

Now consider remote device 14 with reference to FIG. The message carrier optical carrier wavelength signal λ0 is transmitted to the photodetecting antenna receiver 3.
Collision with 5. The output of receiver 55 is connected to a pair of high-Q preamplifier circuits 110 and 120, which only transmit these modulated signals to subcarrier frequencies fl and f2 being transmitted by the base equipment. are passed through to their respective outputs for demodulation. Therefore, only signals having subcarrier frequency f, generated by base unit 12, pass through high-Q preamplifier circuit 110, and signals having subcarrier frequency v1 .
Only signals with fz pass through high-Q preamplifier circuit 120.

In BASE MENU/PAGE mode, the modulated audio signal is typically modulated to subcarrier frequency fl.

In this regard, the high Qf, preamplifier circuit 110 passes the modulated fl signal to its output, while the high Qf! Preamplifier circuit 120 attenuates, if not completely eliminates, the fl signal from being transmitted to its output.

The output of the f1 circuit 110 is a normal radio frequency limiter circuit 1.
12 and conditions the passing modulated signal to be demodulated. More specifically, limiter 112 adjusts the signal to have a constant amplitude.

The output of limiter 112 is connected to an FM detector demodulator 114, which removes the wavelength carrier signal from the received signal.

FM detector circuit 114 will now be considered in more detail with reference to FIG. FM detector circuit 114 has 115A and 1
It has a pair of outputs, each designated 15B. The first output is connected to f1 squelch gate 118 via connector 115A.

The second output is connected to signal validity circuit 76 via connector 115B.
is connected to. FM detector circuit 114 is a conventional FM detection demodulator l) and demodulates the audio signal from the f1 subcarrier frequency.

A signal output at connector 115A of FM detector 114 is generated by the customer via microphone 20 and transmitted as an incoming audible signal. The output signal of connector 115B is a dc level indication of the received radio frequency signal. The signal validity circuit 116 uses this signal to
Determine whether the received radio frequency signal passed by the M detector 114 is valid for the purpose of suppressing extraneous or noisy signals from the audible signal, and the valid audible signal is described in more detail below. so that it can be amplified as described in .

If the signal validation circuit 116 determines that a valid dc level indication of the radio frequency signal exists, it generates a grant signal at its output, indicated at 117. Output 1
17 is connected to the audio output control gate 130, and the output 130A of this gate is connected to the final stage audio amplifier processing circuit 13.
Connect to 2.

In this configuration, amplifier 132 can be powered by audio output control gate 130. amplifier 1
The output of 32 is connected to a remote device speaker or earphone, such as earphone 133, for audibility by an attendant located at remote device 14.

To amplify only the audible signal, remote unit 14 also includes a receivable or squelch signal 1113. Squelch gate 112 ), when enabled, communicates the audible output of FM detector 114 to summing amplifier 131 . Summing amplifier 131 has its output connected to audio amplifier 132 via line 131A. Squelch gate 118 is controlled by signal validity circuit 116 and is connected to output 117. Therefore, if the output of signal validity circuit 116 is positive, squelch 118 will only pass the audible signal. In this way, the signal validity circuit 11
The audible signal is allowed to be amplified only if 6 generates a enable signal. In this way, extraneous or FM noise signals are blocked and only the real signals are passed.

Referring now to FIGS. 3 and 5, the audio amplifier process or final stage amplifier circuit 152 will now be considered in detail.

For signal conditioning, audio amplifier processing circuit 132 includes de-emphasis circuit 161, expansion circuit 165, and amplifier circuit 165. The output of the adder circuit 131 is connected to the input of the de-emphasis circuit 161. De-emphasis circuit 161 conveys this signal via its output 162 to the input of expansion circuit 163. Expansion circuit 16
3 conveys this signal to the input of amplifier circuit 165. Amplifier circuit 165 has another input connected to audio output control circuit 130. Thus, in the presence of an input signal received from the audio output control gate 130, power is applied to the audio amplifier processing circuit 165 so that the audible signal can be amplified by the amplifier 165.

Next, referring to FIG. 7, the signal validity or verification circuit 116
Let's consider this in detail. Signal validation circuit 116 consists of a standard amplitude comparator circuit 151 and a reference level signal source 152. Comparator circuit 151 compares the dc level representation of the received radio frequency produced by demodulator 114 to reference level signal source 152 . The dc level indication signal from demodulator 114 is applied to positive input 153 of comparator 151. Reference level 152 is connected to negative input 154 of comparator 151.

Thus, appearing at the output 115B of the demodulator 114,
Only these limited radio frequency signal levels above some predetermined amplitude will be transmitted. The output of the signal validation circuit 116 is therefore utilized by the fl squelch gate 118 to eliminate unwanted frequencies that were inadvertently passed on by the high-Q preamplifier circuit and thus might otherwise have caused unwanted noise to be reproduced. suppresses, or does not pass, signals that have

The output 117 of the comparator circuit 151 is sent to the squelch or reception enable gate 118 circuit, and to the audio output control circuit 13.
Connected to 0.

Next, consider the operation of signal validation circuit 116.

The input signal received from demodulator circuit 114 is at reference level 1.
52, the signal validity circuit 116
generates an enable logic signal at its output. The input signal received from the FM detector 114 is a dc level indication of the received radio frequency signal. Signal validity circuit 11
6, the squelch or receive enable gate 118 conveys the demodulated audio signal from the demodulator 114 to the summing amplifier 131, where it is amplified and listened to by the user via the earphone 133. can be taken. It should be understood that using other well-known techniques, the modulated signals received at the FM detector are limited to only those audible signals modulated to the subcarrier frequency fl and transmitted to the remote device. However, the preferred method described herein is not a limitation of the present invention.

2 Remote device (a) M-NU”! - firstly, a remote device such as remote device 14 and a remote customer location 2;
Let us consider the communication path between 2 and 2.

The table communication mode is described below in "MENU J It is called a mode.

As best seen in FIGS. 1 and 3, remote device 1
An attendant located at 4 initiates communication with remote customer location 22 by utilizing a control module 90 that includes a pair of switches 90A and 90B, designated MENU and PAGE, respectively. As explained in more detail below, an attendant located at a remote device can switch the switch? O
If you activate PAGE mode by pressing B,
without the message being transmitted to the remote customer location 22.
A user can communicate with all remote devices within device 10. If the user activates MENU mode by pressing switch 90A, the user can communicate with remote customer location 22 and all remote devices in the device will
This communication may be received via a retransmission or repeat feature within base station 12. This retransmission feature is explained in more detail below.

When a user at a remote device decides to communicate with a customer at remote customer location 22, the user initiates communication by pressing and closing switch 90A on control module 90. This selects the MENU mode of communication. The contact output of the control module switch 90A is
It is connected to the input of the mode selection circuit 91. The mode selection circuit 91 determines which mode of communication has been selected (MEN
U or PAGE). Mode selection circuit 91 has two outputs. The first output is connected to a VCO frequency control circuit 97 via a connector 91A. Second
The output of is connected to transmit or logic gate 92 via connector 92A.

Next, mode selection circuit 91 will be considered in more detail with reference to FIG. Mode selection circuit 91 performs two functions: MENU or PAGE switch 90A and ? OB is activated in each control module 90 by enabling logic gate 92 and generating an appropriate logic signal representing when PAGE switch 90B is pressed. This second logic signal is connected to the VCO frequency control circuit 97 via the connector 91A, as described above.

Referring now to FIG. 5, the output signal generated by mode selection circuit 91 will be considered in more detail. The first output signal of mode selection circuit 91 is connected to vCO frequency circuit 97 via 91A and is used to select or control the modulated subcarrier frequency, which modulated carrier frequency is It will be applied to the outgoing audible signal of remote device 14. Since the operation of the VCO frequency control circuit 97 is almost the same as that of the above-mentioned vCO frequency control circuit 44,
Circuit 97 will not be described in further detail. However, circuit 97 is not controlled by foot switch 29, but by MENU and PAGE switches 90A and 90B, respectively, via mode selection circuit 91, and sends frequency signals f3 and f4 in place of f and f2. It is noteworthy that this occurs. Further, the mode selection circuit 91 normally selects f, the subcarrier frequency. Therefore, if the user presses the PAGE switch 90B selecting frequency f4 and then releases the PAGE switch 90B, the mode selection circuit 91 will automatically select the next subcarrier frequency for the next transmission.

A second output of the mode selection circuit 91 is connected to a transmit or logic gate 92 whose output is connected to a transmit enable or XMT gate 93. Send enable gate 95 may cause outgoing voice messages to be transmitted to base station 12, as described in more detail below.

Did the user press the MENU switch? When the OA is activated, it verbally conveys a message via a headset microphone 94 whose output is connected to an audio processing circuit 95. Audio processing circuit 95 amplifies, equalizes, and compresses the signal for modulation.

Next, with reference to FIG. 6, the audio processing circuit 95 will be considered in more detail. This audio processing circuit 95 includes a limiter circuit 95A, a preamplifier circuit 95B, a compression amount circuit 95C1, and a pre-emphasis circuit 95D, which are connected in series with each other for signal conditioning purposes. The output of microphone 94 is coupled to the input of limiter circuit 95A, and the input to remote or COM VCO circuit 96 is coupled to the output of pre-emphasis circuit 95D. The output of the audio processing circuit 95 is connected to a common voltage controlled oscillator 96 which modulates the outgoing audio signal to a predetermined subcarrier frequency f3.

The output of the transmission gate 93 is connected to a light emitting diode drive circuit 99. Therefore, the modulated signal is
, it is still modulated to a single wavelength λ0 and transmitted to all other remote devices as well as the base device 12.

Logic gate 92 will now be considered in more detail with reference to FIG. The output of logic gate 92 connects to XMT gate 93, and whenever logic gate 92 is positive,
Allows the XMT gate to pass the modulated signal. Logic gate 92 has two inputs, and if either of them is true, its output can be true. 1 is driven by the output of the selection circuit 91, so that whenever the user selects either the MENU mode or the PAGE mode of transmission (which will be explained in more detail below), the logic gate 92 selects the XMT The modulated signal is passed through the gate 93. Another input to logic gate 92 connects to footswitch control switch 90C, which will be described in more detail below. However, whenever footswitch control switch 90C is activated, the output of logic gate 92 will be enabled if the output signal of signal validation circuit 126 is true.
This thing is f! It would indicate that an audible signal modulated on the subcarrier frequency is being received. Therefore, whenever the footswitch control switch qoc is activated and an audible signal modulated to the f2 subcarrier frequency is received by the remote device, logic gate 92 will be positive and therefore XMT gate 93 will be used. enable. When the XMT gate 93 is enabled in this manner, the mode of communication is referred to as the BASE FOOTSWITCH mode (described in more detail below).

The output of the light emitter drive circuit 99 is connected to the input of the transmitting antenna 33. In this configuration, subcarrier frequency f3
The transmitted audible signal is then modulated to a single wavelength λ0 via an emitter or emitting optical antenna 33 which transmits a message-carrying signal to the base station 12. Therefore, the signal emitted by the emitter 33 is transmitted to the base device 1
2 receiver 30 as well as the receivers of all remote devices, including remote device 14 .

In order to isolate the remote device's receiver 35 from the infrared transmit signal being transmitted by its emitter 33, the output of the receiver 35 is connected to a high-Q preamplifier circuit 110 and 120, which Only signals having subcarrier frequencies generated by the base equipment are allowed to pass through the circuit.

Next, base equipment 12 will be considered with reference to FIG. The message-carrying optical signal transmitted at the 20 frequency impinges on a photodetector receptor or antenna 50. The output of the receiver 30 is connected to a high Q preamplifier circuit 70 and 80 which passes only the signal having the subcarrier frequency being generated by the remote device through it for demodulation purposes. allow you to do so. Therefore, only signals with subcarrier frequencies generated by remote devices are sent to their respective MENU
and selectively through PAGE preamplifier circuits 70 and 80.

In FIG. 2, in MENU mode, the modulated audio signal is modulated onto the subcarrier frequency. In this regard, ME
NU preamplifier circuit 70 passes the modulated signal to its output, while PAGE preamplifier circuit 80 attenuates, if not entirely eliminates, passing the modulated signal to its output.

The output of the MENU preamplifier circuit 70 is connected to a conventional radio frequency limiter circuit 72 and conditioned to demodulate the passing signal.

The output of limiter 72 is connected to an FM detector demodulator 74, which removes the carrier frequency signal from the received signal. Therefore, the output of FM detector 74 is a transmitted version of the outgoing audible signal generated by the remote device user via handset microphone 94. FM detector 74 has a second output, which is connected to a signal validity circuit 76 that determines whether a valid signal is present. If signal validation circuit 76 determines that a valid signal is present, it generates a receive grant signal at its output.

The output of signal validation circuit 76 is connected to MENU squelch gate 78 and logic gate 45, as shown by line 76A. The output of the MENU squelch gate 78 connects to the aforementioned audio processing speaker relay circuit 40 so that the outgoing audible signal transmitted by the remote device can be heard by the customer through the speaker 18.

Summing amplifier 41 also has an input and is connected to the output cuff 8AIC of MENU squelch gate 78 in order to cause all remote devices to receive the transmitted outgoing audible signal. Accordingly, the outgoing audio signal received by base station 12 is then transmitted via base voltage controlled oscillator 43, as previously described.
It can be modulated to subcarrier frequency f1. This modulated signal is then sent to the emitter drive circuit 4? connected to the output of the transmission gate 47? via to the base emitter 28. The output of logic gate 45 is driven positive, thus allowing transmit gate 47 to pass the modulated signal from base vCO circuit 43 via the signal received by MENU squelch circuit 78. It should therefore be understood that the transmit gate 45 allows the transmission of the modulated outgoing audio signal to all remote devices.

It should be understood that base station 12 also returns modulated outgoing audio signals to the remote station that generated the outgoing audio signals. This message is therefore received by the remote device, passed through the high Qf circuit 110, demodulated, and heard via the remote device earpiece 133 to the person who originated the verbal message. This effect, known as ring sidetone, informs the user that the generated message was correctly received by base station 12 and all remaining remote devices in device 10.

(b) PAGE MODE Next, referring to FIGS. 1-5, the remote device and the base station 12
and all other remote devices. An attendant located at remote device 14 initiates communication to base station 12 by pressing and closing control module 900 page switch 90B and selects the PAGE mode of communication. The control module 900 page switch output is connected to mode selection circuit 91.

When page switch 90B is activated, it causes mode selection circuit 91 to generate a frequency selection signal and a transmit enable signal at its two respective outputs. line 9
The frequency selection output of the mode selection circuit 91 indicated by 12) is connected to the VCO frequency control circuit 97.

Whenever PAGE switch 90B is pressed, mode selection circuit 91 causes VCO frequency control circuit 97 to select the f4 tuned circuit, so voltage controlled oscillator 96 is able to generate the f4 subcarrier frequency and transmit the outgoing audible signal. Modulate. The output of the vCO frequency control circuit 97 is connected to a remote device voltage controlled oscillator 96, where the oscillator 9
6 will modulate the outgoing audio signal to a predetermined subcarrier frequency f4.

The user then communicates a verbal message via bedset microphone 94, which message is transmitted by remote device 14, as previously described.

However, in PAGE mode, the carrier wavelength λ0 is transmitted with the audio signal modulated at the f4 subcarrier frequency as opposed to the f3 subcarrier frequency. Accordingly, the signal emitted by remote unit emitter 33 is received by the base unit 12 as well as all remote unit receivers, including transmitting remote unit 14.

As already pointed out, each remote device within the device
It includes a pair of high Q preamplifier circuits such as circuits 110 and 120. These circuits allow only signals generated by base equipment 12 having subcarrier frequency f1 or f2 to pass through their respective circuits. Thus, although the remote unit receives the transmitted signal modulated to the λ0 carrier wavelength, the radio frequency modulated audio signal is prevented from being demodulated, as described above.

Next, the base device 12 will be considered with reference to FIG. λ0
A message-carrying optical signal transmitted at a wavelength impinges on a photodetector receptor 30. Since the subcarrier frequency of the signal is f4, this signal is passed through the PAGE high-Q preamplifier circuit 80 to its output, while the MENU circuit 7o does not preclude any signal from being passed to its output. However, it will attenuate.

The output of the PAGE circuit 80 is connected to a radio frequency limiter circuit 82 to adjust the passed signal so that it is demodulated.

Limiter circuit 82 is substantially identical to limiter circuit 112 described above, and therefore will not be described in further detail below.

The output of limiter 82 is connected to a conventional FM detection demodulator circuit 84 which removes the subcarrier frequency signal from the received signal. Thus, the outgoing audible signal generated by the remote device user is transmitted via the outgoing headset microphone 94 of the FM detector 84.

FM detector 84 also has a second output, which is connected to signal validity circuit 86 to determine if a valid signal is present. Signal validity circuit 86 is substantially similar to signal validity circuit 76 described above. If signal validation circuit 86 determines that a valid signal is present, it generates a receive grant signal.

The output of the signal validation circuit 86 is the output of the PAGE screen gate 8.
8 and logic enable gate 45 shown by line 86A.
is connected to. The output of PAGE squelch gate 88 is connected only to summing amplifier 41 and not to audio processing speaker relay circuit 40. Therefore, the PAGE signal is not transmitted to the remote customer speaker 18, and therefore the customer cannot hear the transmitted message.

Summing amplifier 41 receives the audible signal passed through PAGE squelch gate 88 and transmit enable gate 47 is opened via the signal generated by the signal validation circuit (via logic gate 45) so that the audible signal It is modulated by voltage controlled oscillator 45 and transmitted to all remote devices as described above.

& Various Transmissions Now, with reference to FIGS. 2 and 3, the operations of the foot switch 29 and the foot switch control switch 90C will be discussed. The foot switch 29 is connected to V via the connector 29A.
In conjunction with CO frequency control circuit 44, vCO frequency control circuit 44 selects the subcarrier frequency at which base station 12 will modulate the transmitted audio signal. The footswitch 29 is also connected to a transmit or logic gate 45 via connector 29B, which gates the XMT gate 47 whenever the footswitch is pressed.
enable, i.e. open. As mentioned above, when footswitch 29 is pressed or activated, the base station utilizes subcarrier frequency f2. Also, as mentioned above, this communication mode is rBAsE FOOTSWIT
This is called CHJ (base foot switch) mode.

Next, consider the BASE FOOTSWITCH mode communication path between base station 12 and a remote device such as remote device 14 and any other remote devices such as remote device 16. A designated person, such as a supervisor, designates one of the remote devices, such as a footswitch control, and instructs an attendant at that remote device to place the footswitch control switch 90C on his or her control module 90 in the active position. Give permission to place. It should be understood that only one remote device, such as remote device 14, can be instructed to place its footswitch control switch 90C in the active position. Therefore,
Other all-footswitch control switches associated with other remote devices will be placed in their inoperative positions, as best seen in FIG.

Typically, whenever a customer at remote location 22 conveys a verbal message, it is modulated onto subcarrier frequency fl before being transmitted to the remote device. Such transmissions will be heard by all remote devices. In order for an agent at a remote base to respond to a customer at a remote customer location 22, the agent first sends an Irj ME message to his or her control module 90.
He must press NU switch 90A and then speak into his remote base microphone, such as microphone 94.

In BASE FOOT8WITCH mode f, the audible signal received from the customer is modulated onto subcarrier frequency f2. Such transmissions are received and audible by all remote devices. For an agent at a remote device to respond to a customer at remote customer location 22, the agent first presses MENU switch 90A on his control module 90 and then speaks into his remote base microphone, such as microphone 94. There must be. Therefore, if the received message is at subcarrier frequency f1 or f! Whether modulated or not, an attendant stationed at a remote device must first press his/her MENU switch 90A to respond to a customer at a remote location.

However, as previously discussed, one remote device is designated to have its footswitch control switch 90C activated. For this designated device, the person assigned to that remote device does not need to press his or her MENU switch 90A;
You can talk directly with customers in 2.

As best seen in FIG. 3, and as previously discussed with respect to a designated remote device such as remote device 14, when that remote device has subcarrier frequency f! The signal generated by signal validity circuit 126 will be true if it receives an audible signal modulated to . If this output signal goes true, the designated remote device's XMT gate 93
made available via. Accordingly, the attendant at the designated remote device will speak into his or her microphone 94. This voice message is modulated onto the f subcarrier frequency and transmitted to the base station 12. When this message is received by base station 12, it is sent back to all remote devices, including the designated remote device. However, the retransmission of the voice message is modulated onto the f2 subcarrier since footswitch 29 is activated. the result,
Due to the annular sidetone effect for the designated remote device 14, the output of the signal validity circuit 126 remains true at 6D, so that hands-free communication can occur.

Next, consider the BASE FOOT8WITCH mode of communication in more detail. BABE FOOTSWITCH
Whenever an optical carrier message is transmitted by base station 12, the signal is transmitted at carrier wavelength λ0 and subcarrier frequency f! is modulated. This optically-carried message signal impinges on all remote unit receivers as well as the base station 12 receiver 30.

As mentioned above, the base station 12 has MENU and PAGE.
High-Q preamplifier circuits 70 and 80 are included, which pass through their selection circuits only signals having subcarrier frequencies f3 or f4 generated by remote devices, such as remote devices 14 and 16. I'm letting you do it. Thus, although base station 12 receives the transmitted signal, this signal is prevented from being demodulated.

Now consider remote device 14 with reference to FIG. wavelength λ
The message-carrying optical signal transmitted at 0 impinges on the photodetector receiver 35. The output of receiver 35 connects to the inputs of both high Q preamplifier circuits 110 and 120. Since the subcarrier frequency is now f2 as opposed to fl, the high-Q preamplifier circuit 120 passes the received signal, while the high-Q
Preamplifier circuit 110 attenuates, if not eliminates, the signal from being transmitted to its output.

The output of the high-Q preamplifier circuit 120 is connected to a radio frequency limiter circuit 122 to condition the one-pass signal to be demodulated. The limiter circuit 122 is different from the limiter circuit 112 described above. The same is true.

The output of limiter circuit 122 is connected to FM detection demodulator circuit 124, which removes the subcarrier frequency from the received signal. Thus, the output of FM detector circuit 124 is a base station transmitted signal generated either by a customer at remote customer location 22 or by a remote device user conveying a verbal message via headset microphone 94. .

FM detector circuit 124 has a second output, which is connected to signal validity circuit 126, which determines whether a valid signal is present. If the signal validation circuit 126 determines that a valid signal is present, it generates a receive grant signal, which is coupled to an audio output control gate 130 whose output is connected to an audio amplifier processing circuit 132.

The output of the signal validity circuit 126 is also connected to the receive permission gate 12.
8, this gate allows the output of FM detector 124 to be sent to summing networker 151. Therefore, the audible signal can be amplified via the adder 131 connected to the input of the audio amplification processing circuit 132.

The output of the signal validity circuit 126 is also a foot switch? D
connected to the open or active terminal of C. In this regard, the grant signal generated by signal validation circuit 126 is coupled to a transmission or logic gate 92 at only one remote device, such as remote device 14. All other transmissions or logic gates on any other remote device are
The output signals of those signal valid circuits cannot be coupled to their transmitting logic gates, but it is
This is because those footswitch control switches, such as the ac, are in the inactive position, thus preventing signals from reaching those logic gates, such as logic gate 92.

The output of logic gate 92 is connected to transmit gate 93, which allows outgoing voice messages generated by active remote device users to be transmitted to the base station, as described above. Therefore, if an attendant is designated and the BASE FOOT8WITCH mode is available for communication, this designated attendant will
Alternatively, one can communicate with remote customer location 22 and all remote devices from anywhere within apparatus 10 without pressing PAGE switches 90A and 90B. This feature thus allows hands-free communication by designated remote device users.

(c) Multiplexed optical wavelength division multiplexing system drawing. In particular, in FIG. Suitable for use as a mutual communication method.

Apparatus 200 typically includes a relay base station or apparatus 212 that optically interconnects a set of similar remote apparatuses or stations, such as remote apparatuses 214 and 216. 2
It will be apparent to those skilled in the art that there may be two remote devices 214 and 216.

A speaker 218, a vehicle detector 219, and a microphone 220 are located at a remote customer location 222 and are connected to the base station 212 via a cable indicated at 225. These devices, including their functionality, are similar to those described with respect to remote customer location 22.

Base station 212 will now be considered in more detail with reference to FIG. The base station 212 includes an emitter 22 for full-duplex optical communication.
8 and receptor 230, base voltage controlled oscillator 245,
A MENU*Q preamplifier 270 and a PAGE high Q preamplifier 280 are included.

Device 200 is similar to device 10, with the following exceptions. Base station 212, emitter 228 and receptor 23
0 are not matched to the same carrier wavelength frequency. In this regard, the emitter transmits a signal at an optical carrier wavelength of 880 nm, denoted λ8, while the receiver receives a signal at a different optical carrier wavelength, denoted λb. Therefore, it should be understood that the signal emitted by the base station emitter is separated from the base station receiver because the emitter and receiver operate at different carrier wavelengths. In this way, light emitted from an emitter, such as emitter 228, will not interfere with light wave communications received by receivers of the same device, such as receiver 230, so that they operate at the same wavelength. If so, no desensitization occurs as would otherwise occur.

Base voltage controlled oscillator 243 is identical to base voltage controlled oscillator 43 previously described with respect to base station 12. MEN
U and PAGE high-Q preamplifiers 270 and 280 are substantially identical to preamplifiers 70 and 80 described above, but
Preamplifiers 70 and 80 transmit optical message carrier beam λ. preamplifier 270 into modulated signals having subcarrier frequencies of f3 and f4, respectively.
and 280 are configured to convert the optical message carrier beam λb into modulated audio signals having subcarrier frequencies fl and f2, respectively.

Now considering the remote devices in more detail with reference to FIG. 9, remote devices 214 and 216 are similar to each other, and only remote device 214 will be described in more detail.

The remote device 214 will now be considered with reference to FIG. Remote unit 214 includes an emitter 233, a receiver 235, remote voltage controlled oscillator and frequency control circuits 296 and 297, and a pair of high Q preamplifiers 210 and 220, respectively. Remote device 214 is substantially similar to remote device 14 described above, except for the differences described below.

To achieve the same separation technique described for base station 212, emitter 233 and receiver 235 are not matched to the same carrier wavelength. Rather, the remote unit receiver 2350 wavelength is matched to the base unit emitter carrier wavelength, 880 nm or λa. Therefore,
The optical message-carrying signals generated by base station 212 may be received by a receiver of each of the remote units, such as remote units 214 and 216.

Similarly, the wavelength of remote device emitter 255 is matched to the carrier wavelength of the base device receiver, ie, wavelength λbK. Accordingly, optically conveyed messages generated by remote device 214 can be received by receiver 230 of base station 212.

The remote unit voltage controlled oscillator frequency controller 297 has a tuned circuit that controls frequencies f1 and f as opposed to f3 and f4.
2 is identical to the voltage controlled oscillator frequency control circuit 97 described with respect to remote unit 14. In this regard, the remote unit voltage controlled oscillator 296:
Carrier frequencies f, and f2 contrasted with f3 and f4
to modulate the audible signal. ) High-Q preamplifiers 410 and 420 are identical to high-Q preamplifiers 110 and 120 previously described with respect to remote device 14.

(Q. Multiple Optical Wavelength Multiplexing with Multiple Subcarrier Frequencies) In the following drawings, and more particularly in FIG. The present invention is constructed in accordance with the present invention and is suitable for use as an intercommunication system.

Apparatus 400 typically includes a relay base station or apparatus 412 that optically interconnects a set of similar remote apparatuses or stations, such as remote apparatuses 414 and 416. Although only two remote devices 414 and 416 are shown for purposes of illustration, it will be apparent to those skilled in the art that many more devices (not shown) may also be used.

A speaker 418, vehicle detector 419 and microphone 420 are located at a remote customer location 422 and are connected to base station 412 via a cable indicated at 425. These devices, including their functionality, are similar to those described with respect to remote customer location 22.

Base station 412 will now be considered in more detail with reference to FIG. The base station 412 includes an emitter 428 and a receiver 430 for full-duplex optical communication, a base voltage controlled oscillator 443,
A MENU' high-Q preamplifier 470 and a PAGE high-Q preamplifier 480 are included.

Device 400 is similar to device 10 with the following exceptions. Base station 412, emitter 428 and receiver 430 are not matched to the same carrier wavelength and therefore operate at different carrier wavelengths. These wavelengths are λa and λ, respectively
Indicated by b. Therefore, the sensitivity of communication reception is not suppressed by light emitted from the same device.

Base voltage controlled oscillator-443 is identical to base voltage controlled oscillator 43 previously described with respect to base station 12. MENU
and PAGE high-Q preamplifiers 470 and 480.
Almost identical to preamplifiers 70 and 80 described above, but
In contrast to converting the optical message-carrying beams 0 into modulated audio signals, this preamplifier 470 and 480
differs in that it is configured to convert the optical message carrying beam λb into a modulated audio signal.

Looking now at the remote devices in more detail with reference to FIG. 10, remote devices 414 and 416 are similar to each other, and only remote device 414 will be discussed in more detail.

Now, with reference to FIG. 10, remote device 414 will be considered in more detail. Remote device 414 includes an emitter 433, a receptor 435, remote voltage controlled oscillator and frequency control circuits 496 and 497, and a pair of high Q preamplifiers 410 and 420, respectively. Remote device 414 is substantially similar to remote device 14 described above with the following differences.

The wavelength of remote device emitter 433 is the same as that of remote device receiver 435.
is not aligned with the carrier wavelength of However, the emitter wavelength is matched to the frequency of base station receiver 430, thus allowing communication between base station 412 and all remote devices within device 400, such as remote devices 414 and 416. ing.

Similarly, the remote device receiver 4350 wavelength is matched to the wavelength of the base station emitter 428, thus allowing communication between all remote devices and the base station 412. This separation technique has been described above with respect to apparatus 200 and will not be described in further detail here.

While particular embodiments of the invention have been disclosed, it will be understood that various modifications may be made within the true spirit and scope of the claims. Therefore, it is not intended to be limited to the precise embodiments disclosed herein.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a functional block diagram of a communication system configured according to the present invention and operating using a single wavelength carrier configuration; FIG. 2 is a functional block diagram of the base station of FIG. 1; Figure 3 is
FIG. 4 is a functional block diagram of the voltage-controlled oscillator frequency control circuit of the base station of FIG. 2. FIG. 5 is a functional block diagram of the typical remote station of FIG. 6. FIG. 6 is a functional block diagram of the audio processing circuit of the remote station in FIG. 3. FIG. 7 is a functional block diagram of the signal validation circuit of the remote station in FIG. 3. is a functional block diagram of the base station audio processing speaker relay circuit of FIG. 2; FIG. 9 is a functional block diagram of another communication scheme constructed in accordance with the present invention and operative utilizing a dual lightwave carrier configuration; and FIG. 10 depict a functional block diagram of yet another communications scheme constructed in accordance with the present invention and operative utilizing a dual optical wavelength carrier configuration. In the figure, 10 is a wireless infrared full-duplex communication system, 12 is a base station, 14.16 is a remote device, 18 is a speaker, 19 is a vehicle detector, 20 is a microphone, 22 is a remote customer location, 2
B, 55.57 is the emitter, 29 is the foot switch, 3
0,55.39 indicate receptors, respectively. Patent Applicant H.M. Electronics.

Claims (26)

[Claims] (1) A wireless optical communication device comprising: means for converting a message into an electrical message-carrying signal; means for modulating the message-carrying signal onto at least one subcarrier frequency signal; and communication means for transmitting the message-carrying subcarrier frequency signal in an optical message-carrying beam. (2) The wireless optical communication device of claim 1, further comprising means for receiving a modulated message-carrying signal in an optical message-carrying beam, and converting means for demodulating the optical message-carrying beam into an electrical message-carrying signal. and the means for receiving the modulated message-carrying signal includes inhibiting the converting means for demodulating the optical message-carrying beam when the optical message-carrying beam is emitted by the communication device. The wireless optical communication device characterized in that the wireless optical communication device includes means. (3) In the wireless optical communication device according to claim (1), the means for connecting further includes means for connecting a microphone thereto to enable the user to input verbal messages for communication. The wireless optical communication device characterized by: (4) A wireless optical communication device according to claim (3), further comprising a microphone physically located at a remote location and electrically connected to the means for connecting the microphone. The wireless optical communication device. (5) The wireless optical communication device of claim (2), wherein the converting means further comprises a speaker connected thereto to enable a user to physically listen to the message-carrying signal received by the device. The wireless optical communication device characterized in that it includes means for: (6) The wireless optical communication device according to claim (5), further comprising a speaker physically located at a remote location and electrically connected to the means for connecting the speaker. The wireless optical communication device. (7) The wireless optical communication device according to claim (1), further comprising control means for selecting at least one subcarrier frequency on which the message carrier signal is to be modulated. The wireless optical communication device. (8) The wireless optical communication device of claim (2), wherein the means for inhibiting includes means for detecting the optical message-carrying beam when it is being emitted by the device. The wireless optical communication device characterized by: (9) The wireless optical communication device according to claim (8), wherein the detecting means is a light receiving diode having a predetermined wavelength. (10) In the wireless optical communication device according to claim (9),
The wireless optical communication device, wherein the transmitting means includes a light emitting diode having a predetermined wavelength. (11) The wireless optical communication device according to claim (10), wherein the light emitting diode and the light receiving diode have the same predetermined wavelength. (12) The wireless optical communication device according to claim (10), wherein the light emitting diode and the light receiving diode have different predetermined wavelengths. (13) a base device for transmitting and receiving an optical message-carrying beam having a predetermined wavelength;
and at least one remote device for receiving, the base device and the remote device each having means for converting a verbal message into an electrical message-carrying signal;
means for modulating a message-carrying signal onto at least one subcarrier frequency signal; communication means for transmitting a message-carrying signal modulated onto an optical message-carrying beam; and means for receiving a message-carrying signal modulated onto an optical carrier beam. , converting means for demodulating an optical message-carrying beam into an electrical message-carrying signal, and means for receiving the modulated message-carrying signal, the optical message-carrying beam being emitted by the apparatus; and means for preventing the converting means from demodulating the optical message carrying beam when received. (14) In the wireless communication system according to claim (13),
The wireless communication system, wherein the means for converting further includes means for connecting a microphone thereto to enable the user to input verbal messages for communication. (15) The wireless communication system according to claim (14), further comprising a microphone physically located at a remote location and electrically connected to the means for connecting the microphone. The wireless communication method. (16) In the wireless communication system according to claim (13),
Said wireless communication system, characterized in that said converting means further includes means for connecting a speaker thereto to enable a user to physically listen to the message-carrying signal received by said device. (17) The wireless communication system according to claim (16), further comprising a speaker physically located at a remote location and electrically connected to the means for connecting the speaker. The wireless communication method. (18) The wireless communication system according to claim (13), further comprising control means for selecting at least one subcarrier frequency signal on which the message carrier signal is to be modulated. The wireless communication method. (19) In the wireless communication system according to claim (13),
The wireless communication system, wherein the means for inhibiting includes means for detecting an optical message-carrying beam when the optical message-carrying beam is being emitted by a device. (20) In the wireless communication system according to claim (19),
The wireless communication system, wherein the detecting means is a light receiving diode having a predetermined wavelength. (21) In the wireless communication system according to claim (20),
The wireless communication system, wherein the transmitting means includes a light emitting diode having a predetermined wavelength. (22) In the wireless communication system according to claim (21),
The wireless communication system, wherein the light emitting diode and the light receiving diode have the same predetermined wavelength. (23) In the wireless communication system according to claim (22),
The light emitting diode and the light receiving diode. The wireless communication system is characterized in that the predetermined wavelengths are different. (24) A transceiver for optical communications, comprising: means for generating a transmitted message frequency signal; means for generating an optical carrier frequency signal; means for modulating the transmitted message frequency signal onto the optical carrier frequency signal; A transceiver comprising: means for receiving an optical carrier frequency signal including a message frequency signal; and means for demodulating a transmitted message frequency signal from the received optical carrier frequency signal. (25) The optical communication transceiver according to claim (24), further comprising: inhibiting the demodulating means when the transmitted message frequency signal is generated by the means for generating a transmitted message frequency signal. The transceiver characterized in that it comprises means for: 26. An optical communications transceiver according to claim 25, wherein said means for inhibiting includes means for detecting a transmitted message frequency signal modulated into an optical message carrying beam.