Abstract:
This invention generally relates to Morse code sending keys systems. More specifically, this invention relates to a wireless key system that can select a particular amateur radio transmitter on a crowded radio bench and direct it to send Morse code messages in a continuous wave (CW) transmission mode without a physical wired connection between the wireless key and said radio transmitter. The wireless keying system is comprised of a Telegraph Instrument Encoding Unit (TIEU) and a Dit/Dah Decoding Unit (DDU). The TIEU electrically encodes the telegraph contact closures and emits an electro-optical signal, mimicking the closures made by the telegraph key. The DDU detects the emitted electro-optical signal and generates electrical signals for keying on and off the amateur radio transmitter chosen. This wireless keying system supports the transfer of Morse code signals from a telegraph hand key, a paddle key, and those generated by a computer.

Description:
BACKGROUND  
       [0001]     1. Field of Invention  
         [0002]     This invention generally relates to Morse code sending key systems. More specifically, this invention relates to a wireless key system that can select a particular amateur radio transmitter on a crowded radio bench and direct it to send Morse code messages in a continuous wave (CW) transmission mode without a physical wired connection between the wireless key and radio transmitter.  
         [0003]     2. Prior Art  
         [0004]     U.S. Pat. No. 5,365,230 to Kikinis discloses a self-contained computer keyboard that communicates keystroke data wirelessly to its host computer via scan codes in a variable magnetic field. This is an inductively coupled system.  
         [0005]     U.S. Pat. No. 5,525,981 to Abernathy shows a cordless transducer/cursor having a transmitter for use in conjunction with the receiver of a digitizer tablet. The transmitter receives parallel binary signals representing the status of non-positional functions and the pressure applied to a stylus and converts these signals into a serial stream of binary data for electrostatic or electromagnetic transmission to the receiver which converts this stream of data into a plurality of parallel signals consistent with those sent by the transmitter. U.S. Pat. No. 6,477,357 to Cook discloses the construction of a customizable wireless device such as a wireless phone from a group of stackable modules which can be fastened together in a variety of configurations. U.S. Pat. No. 6,418,323 to Bright shows a cell phone that includes a “dit” button and a “dah” button and sending and receiving circuitry for Morse code communication when non-verbal secrecy is called for in a public place voice communication. The present invention translates the telegraph contact closures or computer Serial Corn Port signals into electro-optical signals for detection by a close distance line of sight optical decoder.  
         [0006]     Telegraph operators of commercial, military and amateur radio stations have used telegraph keys connected to electrical wires and cables. Typically the other end of the wire or cable is terminated with a plug which inserts into the transmitter or transceiver&#39;s key or paddle jack.  
         [0007]     The major users of this technology to transmit Morse code today are the amateur radio operators who have multiple systems on a limited space bench with a jumble of interconnecting wires. It is also a common practice to have a personal computer and keyboard in the area connected to one of the systems as well as microphones, digital communication interfaces, power amplifiers, speakers, audio processing equipment, antennas, ground connections and power connections.  
         [0008]     Definitions: 
        Morse Code—the Continental or International Code that is the universal standard for radio telegraph communications and is the code used by amateur radio operators.     CW—continuous wave is the description used by amateur radio operators that implies operating the transmitter using Morse code.     Contesting—the act of demonstrating proficiency in the use of Morse code by an operator who makes as many contacts with other stations as possible in a given amount of time and within a given set of rules.     Dit—the basic unit of length, same as a dot and same as a short.     Dah—is equal in length to 3 dits, same as a dash or a long.     Keying—general term used to describe the opening and closing of the telegraph key or paddle which results in turning on and off of the transmitter.     Station—the various transmitters and/or receivers along with associated equipment typically in an amateur radio setup.     Keyed—describes the state of a transmitter or transceiver being in the state of CW transmission.     Iambic Keying—the act of sending an alternating sequence of dits and dahs as long as both the dit and dah paddles are depressed or squeezed.     Transceiver—a receiver and transmitter integrated into one unit.     Hand Key—a single lever telegraph key which when depressed makes an electrical contact between its two terminals and is said to be closed or on. When the lever is not depressed, the key is said to be open or off.     Telegraph Paddle—Single Lever—when the lever is not pressed the paddle is said to be open or off. When the paddle is pressed in either direction, electrical contact is made between either the dit or dah contact and the common terminal.     Telegraph Paddle—Dual Lever—when both levers are not pressed the paddle is said to be open or Off. When either lever is pressed electrical contact is made between either the dit or the dah terminal and the common or ground terminal. The two levers make contact to the common terminal independent of each other. Pressing both levers simultaneously signals the system that Iambic Keying is to be performed.     DTR—Data Terminal Ready     RTS—Ready To Send        
 
       SUMMARY  
       [0024]     Moving the telegraph sending instrument from one transceiver to another is a difficult and cumbersome task due to the number of wires and cables attached to the back of the transceiver. The transceiver is not easily moved and is hard to see behind in the typical bench or shelf set-up. The workspace in front of the transceiver is also crowded due to the various modes operation used by the amateur radio operator. This space usually contains microphones, telegraph keys and paddles along with other accessories. Since the sending unit is electrically connected to the transceiver and the antenna, the possibility of electrical shock to the operator is great in the event of a power and/or grounding problem. When multiple transceivers are in use, as in a single operator contesting mode where time is of the essence, the use of a dedicated key for each transmitter is the costly and often less than satisfactory solution as each key has its own feel and touch and can slow the operator or generate errors in transmission. The addition of a personal computer for sending Morse code typically requires the use of an external CW interface unit which connects between the computer and transceiver with accompanying cabling adding to the congestion.  
         [0025]     The objectives of the Wireless Keying System for a Continuous Wave (CW) Amateur Radio Transmitter are: to provide a Dit/Dah Decoding unit that has selectable output switching to one of a plurality of outputs, moving the connection to subsequent transceivers; to provide a non-physical connection of the sending unit to the transceiver and/or transmitter through the use of an infrared signal in place of wires, making the bench less cluttered and allowing sending unit storage off the bench when not in use; isolating the operator from electrical shock from a grounding or power problem; to provide a system that allows for rapid switching that eliminates the need for multiple sending units and the differences in feel and touch between multiple sending units; to provide an encoding unit that accepts input from all standard telegraph key systems; and to provide an encoding unit that accepts a signal directly from a computer&#39;s serial COM port eliminating the need for an external CW interface.  
       BRIEF SUMMARY OF INVENTION  
       [0026]     The Wireless Keying System for a Continuous Wave (CW) Amateur Radio Transmitter embodies two new units added to a conventional amateur radio station. The first unit is a Telegraph Instrument Encoding Unit or TIEU. When a TIEU is connected to a telegraph sending instrument, shown in phantom lines in the accompanying drawings and not part of this invention, it emits an encoded electro-optical signal representing the action of that telegraph sending instrument lever or levers. The electro-optical signal is made of a series of pulses of three fixed frequencies of F dit , F dah , and F iambic  representing the sending of a dit, dah, and the iambic condition respectively. The second unit is the Dit/Dah Decoding Unit or DDU. It receives, amplifies and decodes the electro-optical signal emitted by the TIEU, recreating the electrical Dit and Dah keying signals corresponding to the action made by the telegraph sending instrument lever or levers and routes the keying signals to the selected one of the several transmitters also shown in phantom lines and not part of this invention. 
     
    
     DRAWINGS  
       [0027]     In order that the invention may be more fully understood it will now be described by way of example, with reference to the accompanying drawings in which  
         [0028]      FIG. 1  is a block diagram showing TIEU and DDU inputs and outputs  
         [0029]      FIG. 2  is a block diagram showing a TIEU interfaced to a Single Lever Telegraph Paddle  
         [0030]      FIG. 3  is a block diagram showing a TIEU interfaced to a Dual Lever Telegraph Paddle  
         [0031]      FIG. 4  is a block diagram showing a TIEU interfaced to a Telegraph Hand or Straight Key  
         [0032]      FIG. 5  is a block diagram showing a TIEU interfaced to a Personal Computer.  
         [0033]      FIG. 6  is a block diagram showing a TIEU and DDU configured in a typical application.  
         [0034]      FIG. 7  is a block diagram showing a DDU configured with a Wired Telegraph Hand or Straight Key.  
         [0035]      FIG. 8  is a block diagram showing a DDU configured with a Wired Dual Lever Telegraph Paddle.  
         [0036]      FIG. 9  is a block diagram showing a Telegraph Encoding Unit detailing the oscillators.  
         [0037]      FIG. 10  is a block diagram showing a Dit/Dah decoding unit detailing the decoders.  
         [0038]      FIG. 11  shows the Morse code lever sequence and the respective electro-optical signal for the Morse Character “A” for the system configured as in  FIG. 4 .  
         [0039]      FIG. 12  shows the Morse code lever sequence and the respective electro-optical signal for the Morse Character “A” for the system as configured in  FIG. 2 .  
         [0040]      FIG. 13  shows the Morse code lever sequence and the respective electro-optical signal for the Morse Character “A” for the system as configured in  FIG. 3 .  
         [0041]      FIG. 14  shows the Serial Corn Port signal sequence and the respective electro-optical signal for the Morse Character “A” for the system as configured in  FIG. 5 .  
         [0042]      FIG. 15  is a block diagram showing a typical Prior Art installation of a personal computer interfaced to a transceiver or transmitter using a CW Interface.  
         [0043]      FIG. 16  is a schematic of the Telegraph Instrument Encoding Unit.  
         [0044]      FIG. 17  is a schematic of the Dit/Dah Decoding Unit. 
     
    
     REFERENCE NUMERALS  
       [0000]    
       
           10 —Wireless Keying System for a Continuous Wave (CW) Amateur Radio Transmitter  
           12 —Telegraph Instrument Encoding Unit (TIEU)  
           14 —Dit/Dah Decoding Unit (DDU)  
           16 —Dah input  
           18 —Dit/Dah Reference input  
           20 —Dit input  
           22 —PCS input  
           24 —D 4 -Electro-optical Emitter/infrared emitting diode  
           26 —D 1 -Electro-optical sensor/infrared photo diode  
           28 —Keyed output/transmitter selector  
           30 —Keyed output T 1   
           32 —Keyed output T 2   
           34 —Keyed output T 3   
           36 —Keyed output T n    
           38 —Auxiliary key input jack  
           40 —Single Lever Telegraph paddle  
           42 —Dah contact  
           44 —Common contact  
           46 —Dit contact  
           48 —Dual Lever Telegraph Paddle  
           50 —Telegraph Hand or Straight Key  
           52 —Key contact (can be connected to either Dit or Dah input)  
           54 —Personal Computer  
           56 —Serial COM port  
           58 —CW Transmitter  1   
           60 —CW Transmitter  2   
           62 —CW Transmitter  3   
           64 —CW Transmitter n  
           66 —Instrument encoder  
           68 —Oscillators  
           70 —LED output Driver Circuitry  
           72 —Amplifier  
           74 —IC 1 -Dah Oscillator  
           76 —IC 2 -Iambic Oscillator  
           78 —IC 3 -Dit Oscillator  
           80 —IC 1 -Dah Decoder  
           82 —IC 2 -Iambic Decoder  
           84 —IC 3 -Dit Decoder  
           86 —IC 4 -Dit and Dah Logic  
           88 —F dit ,  
           90 —F dah ,  
           92 —F iambic    
           94 —CW interface  
           96 —PCG input  
           98 —Straight or Hand lever  
           100 —Single lever  
           102 —Dit lever  
           104 —Dah lever  
           106 —9 volt Battery  
           108 —9 volt Battery  
           110 —power supply jack  
           112 —S 2 -Switch  
           114 —Generic mounting backplate/bracket  
           116 —Dit/Dah Decode  
           118 —Dah keying signal  
           120 —Dit keying signal  
           122 —DDU common  
           124 —Dah auxiliary key input  
           126 —Dit auxiliary key input  
           128 —Common auxiliary key input  
       
     
       DETAILED DESCRIPTION  
       [0105]     In order that the invention may be more fully understood, it will now be described by way of example with reference to the accompanying drawings which represent and illustrate several embodiments of Wireless Keying System for a continuous wave (CW) amateur radio transmitter  10 . Wireless Keying System  10  can be utilized with input from personal computer  54 , Telegraph hand or straight key  50 , single lever telegraph paddle  40 , or dual lever telegraph paddle  48  and its output is easily switched to one of several transmitters  58  through  64  by turning keyed output/transmitter selector  28  to the desired transmitter number.  
         [0106]     Turning to  FIG. 1 , the two units that make up Wireless Keying System  10 , Telegraph Instrument Encoding Unit (TIEU)  12  and Dit/Dah Decoding Unit (DDU)  14 , are represented in block diagrams.  
         [0107]     TIEU  12  is shown with the four possible inputs from the various sending units mentioned above. The inputs that can be received are Dah input  16 , Dit/Dah reference input  18 , Dit input  20  from keys or paddles  40 ,  48  and  50  and PCS input  22  and PCG input  96  from personal computer  54 . The output of TIEU  12  is shown as through D 4 -electro-optical Emitter/infrared emitting diode  24 .  
         [0108]     The input into DDU  14  is shown as through D 1 -electro-optical sensor/infrared photo diode  26 . The output of DDU  14  is selected by turning selector  28  to the transmitter that the operator chooses to use. The auxiliary key input jack  38  is also shown in this view and can be utilized for wired telegraph keys if desired. DDU  14  decodes the electro-optical signal emitted by TIEU  12  and recreates the electrical Dit and Dah keying signals corresponding to the action made by the telegraph sending instrument levers and routes the keying signals through outputs  30  through  36  to one of the plurality of transmitters  58  through  64  respectively. DDU  14  is located on an approximate line of sight with TIEU  12  with a preferred separation of approximately 3 meters or less. D 1 -Electro-optical sensor/infrared photo diode  26  is unaffected by normal levels of room lighting or sun light but some reduced performance of received infrared signal has been observed in the presence of intense direct sunlight or exposure of intense and direct incandescent lighting. Shielding of DDU  14 &#39;s D 1 -sensor  26  improves performance in direct sunlight.  
         [0109]      FIGS. 2, 3 , and  4 , show TIEU  12  mounted to sending Instruments  40 ,  48 , and  50  respectively. These can be mounted using generic mounting backplate/bracket  114  hardware techniques familiar to one skilled in this art, allowing TIEU  12  and the sending instrument to become an integrated unit.  
         [0110]     Electrical Connections:  
         [0111]     The electrical interconnections between TIEU  12  and Single Lever Telegraph Paddle  40  are shown in  FIG. 2 . Dah contact  42 , on Paddle  40 , connects to Dah input  16  on TIEU  12 ; Common contact  44  connects to Dit/Dah Reference input  18 ; and Dit contact  46  connects to Dit input  20 .  
         [0112]     The electrical connections between TIEU  12  and Dual Lever Telegraph Paddle  48  are shown in  FIG. 3 . Here contacts  42 ,  44  and  46  connect again to inputs  16 ,  18  and  20  respectively.  
         [0113]      FIG. 4  shows the electrical connections between TIEU  12  and Telegraph Hand or Straight key  50 . Here, key contact  52  of hand key  50  connects to either the Dah input  16  or the Dit input  20 . The other remains unconnected. Common terminal  44  connects to Dit/Dah Reference input  18 .  
         [0114]      FIG. 5  shows the electrical interface between Personal Computer  54  and TIEU  12 . The Serial COM Port  56  signal (e.g. DTR, RTS) on Personal Computer  54  is electrically connected to PCS input  22  on TIEU  12 . The Signal Ground for Serial COM Port  56  is connected to PCG input  96  on TIEU  12 .  FIG. 15  shows a typical prior art wired set-up for personal computer  54  connecting to a transmitter through CW interface  94 .  
         [0115]      FIG. 6  shows a typical application configuration.  
         [0116]      FIGS. 7 and 8  show DDU  14  configurations utilizing auxiliary key input jack  38  for wired key input from sending instruments  50  and  48  respectively with two conductor cable for straight key  50  and three conductor cable for Dual lever paddle  48 .  
         [0117]     The preceding descriptions are for illustrative purposes and are not intended to limit the scope of this invention. The scope of the invention should be determined by the appended claims rather than by the specific examples given.  
         [0000]     Operation:  
         [0118]      FIGS. 9 and 10  show block diagrams which detail oscillators  68  and Dit/Dah decode  116  sections of TIEU  12  and DDU  14  respectively.  FIG. 16  is the schematic for TIEU  12  showing IC 1 -Oscillator  74 , IC 2 -Oscillator  76  and IC 3 -Oscillator  78  which are Tone decoder/phase-lock loop IC&#39;s.  FIG. 17  is the schematic for DDU  14 . It details IC 1 -Decoder  80 , IC 2 -Decoder  82  and IC 3 -Decoder  84  respectively also as tone decoder/phase-lock loop IC&#39;s.  
         [0119]     TIEU  12  receives its power from internal 9 volt battery  106  when Switch S 1  is closed. When a lever of a telegraph sending instrument is depressed, continuity is established between the lever&#39;s corresponding key contact and the common terminal connection of the telegraph instrument.  
         [0120]     For Straight key  50 , depressing lever  98  causes Dah input  16  to be electrically referenced to Dit/Dah reference input  18 . As a result, IC 1 -Dah Oscillator  74  is enabled and oscillates at a predetermined frequency of F dah =3000 hertz, and remains running or oscillating at that frequency as long as lever  98  is depressed as shown in  FIG. 11 .  
         [0121]     For Single Lever Paddle  40 , depressing lever  100  to the Dit position causes Dit input  20  to be electrically referenced to Dit/Dah reference input  18  of TIEU  12 . As a result IC 3 -Dit Oscillator  78  is enabled and oscillates at a predetermined frequency of F dit =5000 hertz and remains running or oscillating at that frequency as long as the lever remains depressed. Depressing lever  100  of telegraph paddle  40  to the Dah position causes Dah input  16  to be electrically referenced to Dit/Dah Reference input  18 . As a result IC 1 -Dah oscillator  74  is enabled and oscillates at a predetermined frequency of F dah =3000 hertz and remains running at that frequency as long as the lever remains depressed as shown in  FIG. 12 .  
         [0122]     For Dual Lever Telegraph paddle  48 , depressing Dit Lever  102  causes Dit Input  20  to be electrically referenced to the Dit/Dah Reference input  18 . As a result IC 3 -Dit Oscillator  78  is enabled and oscillates at a predetermined frequency of F dit =5000 hertz and remains running at that frequency as long as Lever  102  remains depressed. Depressing Dah Lever  104  causes Dah Input  16  to be electrically referenced to the Dit/Dah Reference input  18 . As a result IC 1 -Dah oscillator  74  is enabled and oscillates at a predetermined frequency of F dah =3000 hertz and remains running at that frequency as long as Lever  104  remains depressed. Depressing or squeezing both Dit and Dah Levers  102  and  104  respectively causes both Dit and Dah inputs  20  and  16  respectively to be electrically referenced to Dit/Dah reference input  18 . As a result, both IC 3 -Dit and IC 1 -Dah Oscillators,  78  and  74  respectively, are disabled and IC 2 -Iambic Oscillator  76  is enabled and oscillates at a predetermined frequency I ambic =7000 hertz and remains running at that frequency as long as both levers  102  and  104  remain depressed as shown in  FIG. 13 . As soon as one of the levers is released, IC 2 -Iambic Oscillator  76  is disabled and the oscillator for the corresponding remaining depressed lever begins to oscillate at its predetermined frequency.  
         [0123]     For Morse code signals generated by Personal Computer  54 , a code program generates a Serial Corn Port  56  signal (e.g. DTR, RTS) causing PCS input  22  to be electrically referenced above PCG input  96  of TIEU  12 . As a result IC 3 -Dit Oscillator  78  is enabled and oscillates at its predetermined frequency of 5000 hertz and remains running at that frequency as long as so directed by the computer&#39;s program as shown in  FIG. 14 .  
         [0124]     An electro-optical signal is generated as the result of one of the three oscillators  68  being applied to LED output Driver Circuitry  70  which causes D 4 -infrared emitting diode  24  to switch on and off at the frequency of the corresponding oscillator. It is this infrared electro-optical signal which provides the wireless keying information which is detected and decoded by DDU  14 .  
         [0125]     DDU  14  acquires power from either a 9 volt battery  108  or from external 9 VDC power supply by power supply jack  110  with S 2 -Switch  112 . DDU  14  detects the presence of the emitted electro-optical signal from TIEU  12  by using infrared photo diode  26 . The electrical response from D 1 -photo diode  26  is amplified by Amplifier  72  to a sufficient level for application of frequency detection as shown in  FIG. 10 . The amplified signal is applied to the IC 3 -Dit Decoder  84 , IC 1 -Dah Decoder  80  and IC 2 -Iambic Decoder  82  as shown in  FIG. 10 . If the applied frequency is within the control range of IC 3 -Dit Decoder  84 , a state change occurs in the decoder&#39;s output. This changed state remains as long as the frequency is within the decoder&#39;s control range. If the applied frequency is within the control range of IC 1 -Dah Decoder  80 , a state change occurs in the decoder&#39;s output. This changed state remains as long as the frequency is within the decoder&#39;s control range. Likewise, if the applied frequency is within the control range of IC 2 -Iambic Decoder  82 , a state change occurs in the decoder&#39;s output. This changed state remains as long as the frequency is within the decoder&#39;s control range. A state change in any of the three decoder&#39;s output is interpreted by DDU  14  as a closed lever condition of the telegraph sending instrument. The duration of the state change is controlled by the amount of time that a telegraph sending instrument lever is depressed or squeezed by the operator. The three output signals from the frequency decoders are further decoded to two separate logic signals, i.e., Dah and Dit as shown in  FIG. 17  after IC 5  and IC 6 . The Dit and Dah logic signals are buffered providing isolation, utilizing IC 5  for the Dah signal and IC 6  for the Dit signal and are routed to one of plurality of outputs,  30  through  36 , as determined by the position of selector  28 . Each output is comprised of Dit keying signal  120 , and Dah keying signal  118  and a DDU common  122 , as shown in  FIGS. 10 and 17 .  
         [0126]     When straight key  50  is used, Dah signal  118  or Dit keying signal  120  is available at the output when key contact  52  is connected to the Dah input  16  or the Dit input  20  of TIEU  12  respectively. The output connects to the Amateur radio transmitter&#39;s paddle jack (not Shown). When paddle  40  or  48  is used both Dit keying signal  120  and Dah keying signal  118  are available at the output and connect to the amateur radio transmitter&#39;s paddle jack. Auxiliary Key Input Jack  38  allows the use of a wired telegraph sending instrument, hand key or paddle, and is selectable to one of a plurality of outputs as determined by the position of selector  28 . Auxiliary Key Input Jack  38  supports the use of traditional wired keys.  
         [0127]      FIGS. 11, 12 ,  13  and  14  illustrate open and closed lever positions and their corresponding frequency distributions from D 4 -electro-optical emitter  24  for the Morse code representation of the letter “A” for TIEU  12  interfaced to hand or straight key  50 , to Single Lever Paddle  40 , to Dual Lever Paddle  48  and to Personal Computer  54  respectively.  
         [0000]     Circuitry TIEU:  
         [0128]     Turning to  FIG. 16 , key contacts of the telegraph sending instrument (hand key  50  or paddles  40  and  48 ) are electrically connected to Dah, Dit and Dah/Dit Reference points  16 ,  20  and  18  respectively on TIEU  12 .  
         [0129]     One terminal of hand key  50  is connected to either Dah input  16  or Dit input  20  and the other terminal is connected to Dah/Dit Reference input  18 .  
         [0130]     For a Single or Dual Lever telegraph paddle  40  or  48 , Dah contact  42  is connected to Dah input  16 , Dit contact  46  is connected to Dit input  20  and common contact  44  is connected to Dit/Dah Reference  18 .  
         [0131]     For Morse code generated by a computer, Serial COM Port  56  signals (e.g. DTR or RTS) connect to PCS input  22  on TIEU  12  and Serial COM Port ground connects from PC  54  to PCG input  96  on TIEU  12 .  
         [0132]     The circuitry of TIEU  12  is powered by a 9 volt battery  106  when switch S 1  is closed.  
         [0133]     When a telegraph lever is depressed or closed, the corresponding telegraph contact completes the circuit and electrically references the corresponding Dit or Dah input on TIEU  12  to Dit/Dah Reference input  18 . The state of the telegraph sending instrument levers and resultant key contact states, i.e., open or closed, are determined by the transistor pairs Q 1  and Q 2 , Q 3  and Q 4 , and Q 5  and Q 6 . These transistor pairs allow only one of IC 1 -oscillator  74 , IC 2 -oscillator  76  or IC 3 -oscillator  78  to be enabled at a given time. For Morse code generated by a Personal Computer program, transistor Q 6  detects the state of Serial COM Port  56  signal and controls the enabling of IC 3 -Dit oscillator  78 .  
         [0134]     When Dah input  16  is referenced to Dit/Dah Reference input  18  as a result of Dah lever  104  of telegraph sending instrument being closed, transistor Q 1  turns on completing the ground path for pin  7  of IC 1 -Dah Oscillator  74 . As a result, a fixed oscillation occurs on pin  8  of IC 1 -Dah oscillator  74 . IC 1 -Dah Oscillator  74  has an oscillation frequency of 3000 hertz as determined by capacitance C 1  and resistance R 5 . When Dah lever  104  of telegraph sending Instrument is opened, transistor Q 1  turns off, opening the ground path for pin  7  of IC 1 -Dah Oscillator  74 , causing the fixed oscillation on pin  8  of IC 1 -Dah Oscillator  74  to stop.  
         [0135]     Similarly, When Dit input  20  is referenced to Dit/Dah Reference input  18  as a result of the Dit lever  102  on telegraph sending instrument being closed, transistor Q 6  turns on, completing the ground path for pin  7  of IC 3  Dit Oscillator  78 . As a result, a fixed oscillation occurs on pin  8  of IC 3  Dit oscillator  78 . IC 3 -Dit Oscillator  78  has an oscillation frequency of 5000 hertz as determined by capacitance C 7  and resistance R 7 . When the Dit lever  102  of telegraph sending Instrument is opened, transistor Q 6  turns off, opening the ground path for pin  7  of IC 3  Dit Oscillator  78 , causing the fixed oscillation on pin  8  of IC 3 -Dit Oscillator  78  to stop.  
         [0136]     When both Dah input  16  and Dit input  20  are referenced to Dit/Dah Reference input  18  as a result of the both levers on telegraph sending instrument being closed, transistor Q 2  and Q 5  turn off and transistors Q 3  and Q 4  turn on. The off states of Q 2  and Q 5  prevent a ground path for pin  7  of IC 1 -Dah Oscillator  74  and IC 3 -Dit Oscillator  78  respectively. The on states of Q 3  and Q 4  provide the ground path for pin  7  of IC 2 -Iambic Oscillator  76 . As a result, a fixed oscillation occurs on pin  8  of Iambic Oscillator  76 —IC 2 . Iambic Oscillator  76 —IC 2  has an oscillation frequency of 7000 hertz as determined by capacitance C 4  and resistance R 6 .  
         [0137]     When the Dit lever  102  of telegraph sending Instrument is opened while the Dah lever  104  remains closed, transistor Q 4  turns off and transistor Q 2  turns on. The off state of transistor Q 4  opens the ground path for pin  7  of IC 2 -Iambic Oscillator  76 , causing the fixed oscillation on pin  8  of IC 2 -Iambic oscillator  76  to stop. The on state of transistor Q 2  completes the ground path for pin  7  of IC 1 -Dah Oscillator  74  causing fixed oscillations to occur on pin  8  of IC 1 -Dah Oscillator  74 .  
         [0138]     Similarly, when the Dah lever  104  of telegraph sending Instrument is opened while the Dit lever  102  remains closed, transistor Q 3  turns off and transistor Q 5  turns on. The off state of transistor Q 3  opens the ground path for pin  7  of IC 2 -Iambic Oscillator  76 , causing the fixed oscillation on pin  8  of IC 2 -Iambic Oscillator  76  to stop. The on state of transistor Q 5  completes the ground path for pin  7  of IC 3 -Dit Oscillator  78  causing fixed oscillations to occur on pin  8  of IC 3 -Dit Oscillator  78 . When both levers  102  and  104  of the telegraph sending instrument are opened together, transistors Q 3  and Q 4  turn off, causing the fixed oscillation on pin  8  of IC 2 -Iambic Oscillator  76  to stop.  
         [0139]     When PCS input  22  is at a high level, as instructed by a Morse code program running on Personal Computer  54 , with respect to the PCG input  96 , transistor Q 6  turns on, completing the ground path for pin  7  of IC 3 -Dit Oscillator  78 . As a result, a fixed oscillation of 5000 hertz occurs on pin  8  of IC 3 -Dit Oscillator  78 . This oscillation is determined by capacitance C 7  and resistance R 7 . When the PCS input  22  returns to the low level, as instructed by the Morse code program running on Personal Computer  54 , with respect to PCG input  96 , transistor Q 6  turns off, opening the ground path for pin  7  of IC 3 -Dit Oscillator  78 , causing the fixed oscillations on pin  8  of IC 3 -Dit Oscillator  78  to stop.  
         [0140]     When IC 1 -Dah Oscillator  74  is enabled, capacitance C 10  provides ac-coupling of IC 1 -Dah Oscillator&#39;s  74  output to the base of Transistor Q 7 , providing sufficient switching base current to cause the collector of transistor Q 7  to switch on and off. The on collector current of transistor Q 7  is of a sufficient level as determined by resistance R 12  to cause the D 4 -infrared emitting diode  24  attached to the collector of transistor Q 7  to emit a 3000 hertz infrared electro-optical signal.  
         [0141]     Similarly, when IC 3 -Dit Oscillator  78  is enabled, capacitance C 12  provides ac-coupling of IC 3 -Dit Oscillator  78 &#39;s output to the base of Transistor Q 7 , providing sufficient switching base current to cause the collector of transistor Q 7  to switch on and off. The on collector current of transistor Q 7  is of a sufficient level as determined by resistance R 12  to cause D 4 -infrared emitting diode  24  attached to the collector of transistor Q 7  to emit a 5000 hertz infrared electro-optical signal.  
         [0142]     Likewise, when IC 2 -Iambic Oscillator  76  is enabled, capacitance C 11  provides ac-coupling of IC 2 -Iambic Oscillator  76 &#39;s output to the base of transistor Q 7 , providing sufficient switching base current to cause the collector of transistor Q 7  to switch on and off. The on collector current of transistor Q 7  is of a sufficient level as determined by resistance R 12  to cause D 4 -infrared emitting diode  24  attached to the collector of transistor Q 7  to emit a 7000 hertz infrared electro-optical signal.  
         [0143]     The emission of the 3000 hertz infrared signal from TIEU  12  represents the closure of the telegraph sending instrument&#39;s Dah lever  104 . The emission of the 5000 hertz infrared signal from TIEU  12  represents closure of the telegraph sending instrument&#39;s Dit lever  102 . The emission of the 5000 hertz infrared signal from TIEU  12  can also represent a High level state from a personal computer&#39;s  54  Serial COM Port  56 . The emission of the 7000 hertz infrared signal from TIEU  12  represents the closure of the telegraph sending instrument&#39;s Dit and Dah levers  102  and  104 .  
         [0000]     Circuitry DDU:  
         [0144]     Turning to  FIG. 17 , note the circuit diagram for Dit/Dah Decoding Unit, DDU  14 , which is powered by either internal 9 volt battery  108  or an external 9 VDC supply via power supply jack  110  and is selectable by S 2 -switch  112 .  
         [0145]     When DDU  14  is powered, the optical power from D 1 -infrared photodiode  26  is converted and amplified into a sufficient electrical signal by transistors Q 1  and Q 2 . IC 1 -Dah Decoder  80 , IC 2 -Iambic Decoder  82  and IC 3 -Dit Decoder  84  perform frequency detection and comprise Dit/Dah Decode  116  circuitry of DDU  14 . See  FIG. 10  for details on Dit/Dah Decode  116 . The signal from the collector of transistor Q 2  is applied to the pin  3  inputs of IC 1 -Dah Decoder  80 , IC 2 -Iambic Decoder  82  and IC 3 -Dit Decoder  84  by capacitance C 2 . When the emitted infrared signal from TIEU  12  is within a distance of approximately 3 meters or less of DDU  14 &#39;s D 1 -infrared photodiode  26 , a sufficient signal is present for detection by the frequency decoders. The IC 1 -Dah Decoder  80 , IC 2 -Iambic Decoder  82  and IC 3 -Dit Decoder  84  are designed to lock on frequencies centered about 3000, 7000 and 5000 hertz respectively. These are the three frequencies emitted by TIEU  12 .  
         [0146]     IC 1 -Dah Decoder  80 &#39;s center frequency is determined by capacitance C 3  and resistance R 7 . Its control range is determined primarily by capacitances C 4  and C 5 .  
         [0147]     IC 3 -Dit Decoder  84 &#39;s center frequency is determined by capacitance C 11  and resistance R 9 . Its control range is determined primarily by capacitances C  12  and C 13 .  
         [0148]     IC 2 -Iambic Decoder  82 &#39;s center frequency is determined by capacitance C 7  and resistance R 8 . Its control range is determined primarily by capacitances C 8  and C 9 .  
         [0149]     A state change from high to low occurs on the decoder&#39;s output pin  8  when the applied signal to input pin  3  of the decoder is within the control range of the frequency decoder. The low state remains as long as the frequency stays within the control range of the decoder. A low state in any of the three decoder&#39;s output is interpreted by DDU  14  as a closed lever condition of the telegraph sending instrument. The emission of the 3000 hertz signal from TIEU  12  will cause IC 1 -Dah Decoder  80  output to stay low the amount of time that the telegraph sending instrument&#39;s Dah lever  104  is depressed or squeezed. The emission of the 5000 hertz signal from TIEU  12  will cause IC 3 -Dit Decoder  84  output to stay low the amount of time that the telegraph sending instrument&#39;s Dit lever  102  is depressed or squeezed. The emission of the 7000 hertz signal from TIEU  12  will cause IC 2 -Iambic Decoder  82  output to stay low the amount of time that the telegraph sending instrument&#39;s Dit and Dah levers  102  and  104  are both depressed or squeezed.  
         [0150]     IC 4 -Dit and Dah Logic  86  performs decoding of the three frequency decoder&#39;s outputs. A low state on output pin  8  of either IC 1 -Dah Decoder  80  or IC 2 -Iambic Decoder  82  signifies a Dah condition and a low state on output pin  8  of either IC 3 -Dit Decoder  84  or IC 2 -Iambic Decoder  82  signifies a Dit condition causing a high state on pin  3  and pin  4  of IC 4 -Dit and Dah Logic  86  respectively. The high state of pin  3  of IC 4 -Dit and Dah Logic  86  supplies sufficient current through photodiode of IC 5 , causing the transistor of IC 5  to go low when the collector of transistor of IC 5  is connected to key or paddle jack of an amateur radio transmitter or transceiver by way of Keyed output/transmitter selector  28 . The low condition of the transistor of IC 5  causes the Dah input of the amateur radio transmitter or transceiver to be keyed. Similarly, the high state of pin  4  of IC 4 -Dit and Dah Logic  86  supplies sufficient current through the photodiode of IC 6 , causing the transistor of IC 6  to go low when the collector of transistor IC 6  is connected to key or paddle jack of an amateur radio transmitter or transceiver by way of Keyed output/transmitter selector  28 . The low condition of the transistor of IC 6  causes the Dit input of the amateur radio transmitter to be keyed.  
         [0151]     Keyed output/transmitter selector  28  contains ganged switches S 1 A and S 1 B which provide selection of one of a plurality of keying outputs of DDU  14 . Each keyed output  30  through  36  of DDU  14  is comprised of Dit keying signal  120 , Dah keying signal  118  and DDU common  122 . Keyed outputs  30  through  36  provide the electrical keying connections between DDU  14  and CW Transmitters  58  through  64 .  
         [0152]     DDU  14  also provides auxiliary input jack  38  for use with conventionally wired telegraph sending instruments. Keyed output/transmitter selector  28  ganged switches S 1 A and SIB provide connection of the wired telegraph sending instrument to one of the plurality of keying outputs  30  though  36 .