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Hal Communications DKB-2010 Instruction Manual

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  • Page 2 Mode Keyboards shall be free of defects in materials and workmanship under normal use and service for a period of one year from the date of shipment, and further warrants that all parts supplied with DKB-2010 kits shall likewise be free of such defects for the same period.

  • Page 3: Table Of Contents

    TABLE OF CONTENTS Specifications ................4 Section I: General Information 1.1 Description ............6 1.2 Instrument Identification ........6 1.3 Accessories Furnished ........7 1.4 Manual Preview ..........7 Section II: Installation 2.1 Initial Inspection ..........8 2.2 Preliminary Checkout .......... 8 2.3 CW Transmitter Keying Connections ....
  • Page 4 Figure 5.10: Jumper Placement on Logic Circuit Board Figure 5.11: Weight-Ratio Jumper Placement Figure 5.12: Bottom Cover Assembly Figure 5.13: Assembled DKB-2010 with Bottom Cover Removed Figure 5.14: Diode Placement in Identifier Matrix ........... 44 Figure 6.1: Logic Circuit Board Test Points ............ 50 Figure 6.2: Keyswitch Circuit Board Test Points ..........
  • Page 5 Table 3.1: Characters Produced by Bracketed Keys ........13 Table 4.1: RTTY Timing Chain Output Frequencies ........27 Table 4.2: ASCII Character Codes Used in the DKB-2010 ......36 Table 4.3: ROM Character Input and Output Code ........37 Table 4.4: RTTY Baudot Codes ..............38 Table 4.5: Morse Codes ................

  • Page 6: Specifications

    DKB-2010 SPECIFICATIONS RTTY MODE RTTY Keyfunctions: 10 numeric (0 through 9) Code: 26 alphabetic (A through Z) International Teletype, Baudot 15 punctuation marks: . , : ; / " - ! " # & $ () ' Character Format: 3 carriage control keys: linefeed...
  • Page 7 DKB-2010 SPECIFICATIONS (continued) Morse Mode Morse Keyfunctions: 10 numeric (0 through 9) Code: 26 alphabetic (A through Z) International Morse 9 punctuation marks: . , : ; / " - ' () Data Sense: 5 special character keys: Keyed: output conducting...

  • Page 8: General Information

    I. GENERAL INFORMATION 1.1 Description The HAL DKB-2010 is a solid-state, electronic keyboard designed for transmitting both RTTY (Baudot) and Morse codes. A successor to HAL Communication's popular first-generation keyboards, the DKB-2010 provides many advanced operating features: 1. A three-character buffer memory stores the characters typed for transmission at a constant rate.

  • Page 9: Accessories Furnished

    In the following sections, you will find instructions for installing and operating the DKB-2010. Please read them carefully before attempting to use your keyboard. Section 4 provides a full description of the keyboard circuitry. Step-by-step instructions for constructing the keyboard kit will be found in Section 5;...

  • Page 10: Section Ii: Installation

    II. INSTALLATION 2.1 Initial Inspection When you unpack your DKB-2010 keyboard, examine it carefully. If evidence of shipping damage is found, contact the carrier immediately. Before discarding the packing material, check that all parts and accessories are accounted for (included accessories are listed in Section 1.3). If any are missing, please notify the factory in writing.
  • Page 11 Some transmitters (such as the Yaesu FTDX-560 and several of the Swan transceivers) include a wave- shaping filter in the key line, with a capacitor connected directly across the key terminals. The charge stored in this capacitor can produce a current surge large enough to damage the keyboard switching transistor when the transmitter is keyed.

  • Page 12: Rtty Loop Connections

    2.4 RTTY Loop Connections Since the RTTY output stage of the keyboard is isolated from ground and from the chassis, the keyboard can be connected at any convenient point in the station loop circuit, provided that the voltage from either loop connection to ground does not exceed 250 volts.
  • Page 13 The diode bridge circuit shown in Figure 2.5, if installed at the RTTY LOOP plug, makes it possible to connect the loop leads without regard for polarity. Diode polarity must be carefully observed when constructing the circuit, and the leads must be properly insulated and positioned so that they do not short together.

  • Page 14: Audio Output Connections

    CAUTION: LOOP SUPPLY VOLTAGES ARE EXPOSED AT THE CONTACTS ON THE PLUG. IF YOU USE A HIGH VOLTAGE LOOP SUPPLY, DO NOT SWITCH IT ON UNLESS THE PLUG IS INSERTED INTO THE KEYBOARD RTTY LOOP JACK. Once the connections have been made and the plug inserted, the loop supply and keyboard may be plugged in and switched on.

  • Page 15: Section Iii: Operating Your Keyboard

    III. OPERATING YOUR KEYBOARD 3.1 Introduction The many advanced features of the DKB-2010 keyboard make it easy to produce flawless RTTY and Morse code signals. The operating tips presented in this section will help you take full advantage of your keyboard's capabilities, RTTY operation will be covered first.

  • Page 16: Figure 3.1 Location Of Controls And Keys

    Figure 3.1 Location of Controls and Keys As soon as you type the first character of a series, the keyboard will begin transmitting it. You may then type two more characters, even though transmission of the first one has not been completed. The keyboard will "remember"...

  • Page 17: Morse Code Operation

    3.3 Morse Code Operation Morse codetyping with the DKB-2010 keyboard is very similar to RTTY operation. Set the MODE switch to the Morse position and rotate the volume control clockwise to switch the keyboard on. Allow a few seconds for the identifier circuit to clear itself.

  • Page 18: Section Iv: Theory Of Operation

    Applications (Englewood Cliffs, N. J.: Prentice Hall, Inc., 1970). he ASCII code is the American Standard Code for Information Interchange, widely used in data processing systems. Table 4.2 in Section 4 lists the ASCII code for each character used in the DKB-2010 keyboard.

  • Page 19: Circuit Analysis

    Depending on the setting of the mode switch, the register output activates either the Morse character generator or the RTTY loop switching circuit. In the RTTY mode, the output code keys the loop switch through an isolation circuit. For Morse transmission, the bits must be converted to pulses of unequal length, forming dots and dashes.

  • Page 21: Scanning Keyboard Encoder

    IC's data drivers to transmit the stored character to the keyboard's code The IC's internal memory is actually capable of translating 90 different keys; only 46 are required in the DKB-2010, so the remaining keyswitch positions are left blank.

  • Page 22: Rom Code Converter

    converter via data lines A through A . The data strobe output then goes low, and the memory full lamp is extinguished. If the operator types slower than the data transmission rate, the ENABLE signal is returned to the encoder IC almost instantaneously, so the memory full light is energized only momentarily and therefore does not emit a noticeable flash.

  • Page 23: Rtty Control And Decoding Circuit

    Buffer operation is controlled by the Logic circuit shown at the left in the drawing. When a new character has been produced by the keyboard encoder, the READY line goes high. This signal passes through a NOR gate where it is combined with the ID READY signal. Thus, if a character is ready at either the keyboard or at the identifier, the output of the NOR gate will be low.

  • Page 24: Shift Register And Control Circuit

    The output of each stage in the character timing counter is connected to one of the four inputs of a NAND gate (IC-28). When the counter has received fifteen clock pulses, all of the gates inputs are high. The output goes low, resetting the counter before the sixteenth clock pulse arrives. The reset signal is also fed back to pin 11 of IC-14, stopping the flow of clock pulses to the RTTY SHIFT line.
  • Page 25 through an inverter to drive the gates at the inputs of the shift register stages high, allowing data from the storage buffer to enter. If the keyboard is in the RTTY mode, the line is high, and the Q or "1" output of the first control flip- flop (pin 9 of IC-7) passes through a NAND gate (part of IC-16) to drive the RTTY LOAD line low.
  • Page 26 In the Morse mode, all eight data lines from the storage buffer are available to carry the character code. The M/R and lines are switched to the high and low states, respectively, opening the gates at the inputs of the first, seventh and eighth register stages. Of course, the ROM code converter is instructed to produce the Morse rather than the RTTY character code, as described in Section 4.5.

  • Page 27: Rtty Encoder And Loop Interface

    "end" bit is used by the Morse character generator to produce a space between characters, as explained in Section 4.12. In the RTTY mode, data bits are clocked out of the shift register at a constant rate, as all select pulses are of the same duration, In Morse operation, however, the dashes are three times as long as the dots.

  • Page 28: Figure 4.4: Generation Of The Letters-Shift Code

    As described in Section 4.7, the RTTY control circuit detects when a change of case is necessary. In this instance, the shift register is disabled until after the case code has been transmitted. The register output remains high during this period. Clock pulses are controlled by the logic circuit shown at the left in Figure 8.7.

  • Page 29: Rtty Timing Chain

    The case-change code is coupled through a NAND gate (part of IC-25) and an inverter to IC-33, where it is used in place of the shift register output to control the keying circuit. When the keyboard is switched to the Morse mode, the bus goes low.

  • Page 30: Rtty Character Counter

    Although the output of the RTTY timing chain is not used to clock the shift register in the Morse mode , VHØ and HØ clock pulses are still needed in the keyencoder, buffer control, and RTTY loop interface circuits. The bus is therefore connected through diode D8 to pin 8 of IC-35.

  • Page 31: Figure 4.7 Production Of Dots By The Morse Character Generator

    Figure 4.6 Morse Clock and Decoder Waveform output of IC-31 is connected through an inverter to the J input of the dot flip-flop. The output from one of the remaining lines is selected by the weight control (S302), inverted, and fed to the K input. When the counter is in the "0"...

  • Page 32: Figure 4.8 Production Of Dashes By The Morse Character Generator

    output of the decoder is fed back to the clock input of the oscillator control flip-flop. When the counter has received seven clock pulses, the line goes low. On the eighth clock pulse, it returns to the high state. This positive transition will cause the oscillator control flip-flop to reset if the end of the character has been reached, stopping the oscillator.

  • Page 33: Morse Output Control

    Figure 4.9 Suppression of Extra Dot to Produce Intercharacter Space 4.13 Morse Output Control The Morse output control, shown in Figure 8.11, accepts inputs from the Morse character generator, the BREAK key, and the RTTY character counter. It controls both the transmitter keying transistor and the sidetone oscillator.

  • Page 34: Quick Brown Fox And Id Control

    The oscillator consists of the control gate, two inverters and an RC network which determines the operating frequency. Variable resistor P1 permits adjustment of the frequency. The output of the oscillator (pin 10 of IC-24) drives the base of a current amplifier transistor, Q4. The output signal is developed across the collector load resistor, P302, which controls the level fed to the speaker and, through an isolating capacitor, to the audio output jack.

  • Page 35: Identifier

    The input pulses are derived from the buffer control circuit because the identifier must be instructed to produce each successive output code only when the buffer is ready to receive it. Characters are loaded from the ROM code converter into the buffer when the LOAD BUFFER line goes high momentarily. As shown in Figure 4.10, the RESUME ID line goes low for two HØ...

  • Page 36: Three-Character Sequencer

    increments, the next decoder line goes low, and the code for the next message character appears on the data lines ready to be loaded into the buffer. For reference, a complete listing of the ASCII codes used is given in Table 4.2 in Section 4.18. To initiate the identification cycle, the HERE IS keyswitch is closed, pulling the HERE IS START line low.

  • Page 37: Character Codes

    4.18 Character Codes The tables on the following pages list the various character codes used in the DKB-2010 keyboard. Table 4.2 tabulates that portion of the ASCII character set produced by the keyencoder circuit. Only those ASCII characters which correspond to Military Standard Baudot characters are used. The codes, which...

  • Page 38: Table 4.2: Ascii Character Codes Used In The Dkb-2010

    Table 4.2: ASCII Character Codes Used in the DKB-2010 Unshifted Shifted Unshifted Shifted  A  A  A  A 100 0001 100 0001 011 0111 010 0111 100 0010 100 0010 100 0011 100 0011 100 0100 100 0100...
  • Page 39 Table 4.3: ROM Converter Input and Output Codes...
  • Page 40 Table 4.4: RTTY Baudot Code (Military Standard) Bit Number Case 5 4 3 2 1 Letters Figures 0 0 0 0 0 BLANK BLANK 0 0 0 0 1 0 0 0 1 0 0 0 0 1 1 0 0 1 0 0 SPACE SPACE 0 0 1 0 1...

  • Page 41: Table 4.5: Morse Codes

    Table 4.5: Morse Codes Character Code Character Code · – Ø – – – – – – · · · · – – – – – · – · · · – – – – · · · · · – – ·...

  • Page 42: Assembly Instructions

    V. ASSEMBLY INSTRUCTIONS The DKB-2010 is no longer available in kit form. Chapter V has been deleted from this manual with the exception of Section 5.13 which covers coding of the identifier. 5.13 Coding the Identifier In addition to the regular letter and number keys, the keyboard provides three automatic sequence keys.

  • Page 43: Table 5.1 Coding Chart For Identifier

    Table 5.1 Coding Chart for Identifier Character CQ key AUX key HERE IS...
  • Page 44 Table 5.1 Coding Chart for Identifier Character CQ key AUX key HERE IS...
  • Page 45 As an example, let us assume that the CQ key is to be coded with the three characters C, Q and a space. Here is how we would fill in the chart: Character CQ key SPACE From Table 4.2, we see that the code for the first character, C, is 100 0011. Reversing the order, we have 1100 001, which we enter in the first line of the coding chart.

  • Page 46: Figure 5.14 Diode Placement In Identifier Matrix

    181. Install the bottom cover to the keyboard cabinet, being careful to tuck in the wiring harness so that it is not pinched. Note that the front edge of the cover fits inside the lip of the cabinet. The rear lip of the cover should be on the outside of the rear panel.

  • Page 47: Section Vi: Maintenance

    Service Procedures The DKB-2010 is constructed with high quality materials throughout. The G-10 epoxy-glass circuit boards are used in preference to less costly materials because of their durability. Nonetheless, a reasonable amount of care should be exercised when removing and installing components.
  • Page 48 Symptom: Keyboard dead in both modes; does not key transmitter, sidetone oscillator or teleprinter loop Suggested Tests: Switch the keyboard on by rotating the volume control clockwise. If the pilot lamp does not light, check that the keyboard is plugged into a live outlet delivering 105 to 125 V AC (or 210 to 250 V AC if your unit is wired for nominal 230 volt operation –...
  • Page 49 If the shift register output is satisfactory, the difficulty must either be a result of incorrect connection to the external equipment (RTTY loop and CW transmitter) or must result from a failure of both the RTTY encoder and loop interface circuit (Figure 8.7) and the Morse circuitry, consisting of the Morse character generator (Figure 8.10) and the Morse output control (Figure 8.11).
  • Page 50 Symptom: Keyboard produces incorrect characters or character codes Suggested Tests: Since the elements which determine the character codes are built into the encoder and ROM integrated circuits at the time of manufacture, it is unlikely that they would cause transmission errors. Much more probable is that one or more of the diodes in the memory matrix for the HERE IS sequencer (Figure 8.13) or the three-letter sequencers (Figure 8.14) is reversed or shorted.

  • Page 51: Table 6.1 Test Points - Logic Circuit Board

    Table 6.1 Test Points - Logic Circuit Board Waveform Waveform _________ Resume ID 100 WPM Osc. Buffer Full __________ Letters Case 3, 4 Buffer Read 1, 13 Figures Case 2, 6 Load Buffer RTTY Clock 1, 12 Ready (Gate Output) _____ Enable 75 WPM Osc.

  • Page 52: Figure 6.1 Logic Circuit Board Test Points

    Figure 6.1 Logic Circuit Board Test Points...

  • Page 53: Figure 6.2 Keyswitch Circuit Board Test Points

    Figure 6.2 Keyswitch Circuit Board Test Points...

  • Page 54: Figure 6.3 Power Supply Circuit Board Test Points

    Figure 6.3 Power Supply Circuit Board Test Points...

  • Page 55: Table 6.2 Dkb Logic Board Connector (J305)

    Table 6.2 DKB Logic Board Connector (J305) ________ +5 Volt QBF Start ___________ 66 WPM HERE IS Start ________ 75 WPM AUX Start _______ 100 WPM CQ Start 60 WPM – Loop out (ring _____ Break –12 Volt Morse (M/R) GRID BLOCK + Loop out (tip) CATHODE...
  • Page 56 Table 6.3 DKB Keyboard Connector and DKB Power Supply Keyboard (J306) Power Supply (J307) ________ QBF Start ___________ Transf. Cent. Tap HERE IS Start _____ ˥ BREAK 12.6 Volt AC ˩ +5 Volt A8 (not used) +5 Volt +5 Volt –12 Volt A7 (not used) –12 Volt...

  • Page 57: Table 6.4 Dkb-2010 Wire List

    Table 6.4 DKB-2010 Wire List...

  • Page 58: Table 6.5: Integrated Circuit Pin Numbers For Ground And Power

    Table 6.5 Integrated Circuit Pin Numbers for Ground and Power Connections IC Type Ground +5 Volt –12 Volt MM5213 none 16, 24 (or MM5231) MM5740 7400 7401 7402 7404 7405 7410 7420 7430 7442 7474 7475 7493 7496 74121...

  • Page 59: Section Vii: Parts List

    VII. PARTS LIST (11/75 ed.) Integrated Circuits Resistors MM5213 100 Ω, ¼ Watt MM5740 120 Ω, ¼ Watt 7400 180 Ω, ¼ Watt 7401 220 Ω, ¼ Watt 7402 270 Ω, ¼ Watt 7404 330 Ω, ¼ Watt 7405 390 Ω, ¼ Watt 7410 470 Ω, ¼...
  • Page 60 6107 toroid core type CF102-Q1 Wire 3-conductor power cord DKB-2010 wiring harness 24" length no. 22 tinned bar wire 36" length no. 22 hook-up wire 9" length no. 22 insulated sleeving 48" length no. 30 Strip-eze magnet wire 40"...
  • Page 61 Keyboard Parts Keyswitches Return Springs Spring Retainer Washers Space Bar Hardware Set, consisting of: Space-bar plungers Space-bar guides No. 4 × ¼" screws Space-bar adapter Space-bar torsion bar Keytop Set, consisting of: Space-bar Keytop Blank Keytop Shift Keytops "AUX" Keytop "CQ"...

  • Page 62: Section Viii: Diagrams

    VIII. DIAGRAMS In this section you will find the schematic diagrams and layout drawings for the DKB-2010 keyboard, as listed below. An explanation of the labels and codes used in the schematic diagrams may be found in Section 4.3. The drawing conventions are depicted in Figure 8.2.
  • Page 66 Part List: Figure 8.3: Keyboard Encoder C101 390 pF Disc Ceramic Capacitor C102 - C108 0.1 µF Disc Ceramic Capacitor (16 Volt) R101 - R107 1 kΩ, ¼ Watt Resistor Q101 MPS3702, MPS3703, or MPS6518 PNP Transistor D101 - D138 1N4148 Silicon Diode I101 MM5740AAA/N Integrated Circuit...
  • Page 68 Parts List: Figure 8.4: Buffer Control R1 - R8 6.8 kΩ, ¼ Watt Resistor I1, I2 7474 Integrated Circuit 7402 Integrated Circuit I4, I5 7475 Integrated Circuit MM5213/N, MM5231/N or MM5203/N...
  • Page 70 Parts List: Figure 8.5: RTTY Control and Decoder C1, C2 0.001 µF Disc Ceramic Capacitor 220 pF Disc Ceramic Capacitor 2.2 kΩ, ¼ Watt Resistor 2.7 kΩ, ¼ Watt Resistor R12, R13 10 kΩ, ¼ Watt Resistor 8.2 kΩ, ¼ Watt Resistor R14A 270 Ω, ¼...
  • Page 72 Parts List: Figure 8.6: Shift Register Control 1 kΩ, ¼ Watt Resistor 7474 Integrated Circuit I8, I11 7402 Integrated Circuit I9, I10 7496 Integrated Circuit 7404 Integrated Circuit I16, I18 7400 Integrated Circuit 7405 Integrated Circuit...
  • Page 74 Parts List: Figure 8.7 RTTY Encoder and Loop Interface C4, C5 0.01 µF Disc Ceramic Capacitor C23, C301, C307, C308 0.001 µF Disc Ceramic Capacitor C309 0.1 µF, 400 V Mylar Capacitor 180 Ω, ¼ Watt Resistor 3.3 kΩ, ¼ Watt Resistor 1 kΩ, ¼...
  • Page 76 Parts List: Figure 8.8: RTTY Timing Chain C6 - C13 100 pF Disc Ceramic Capacitor R18, R19, R21 - R24, R33 1 kΩ, ¼ Watt Resistor 390 Ω, ¼ Watt Resistor R25 - R28 1.8 kΩ, ¼ Watt Resistor R29 - R32 560 Ω, ¼...
  • Page 78 Part List: Figure 8.9: RTTY Character Counter 10 µF, 16 Volt Electrolytic Capacitor 1 kΩ, ¼ Watt Resistor 10 kΩ, ¼ Watt Resistor 74121 Integrated Circuit 7404 Integrated Circuit I20, I23 7473 Integrated Circuit 7493 Integrated Circuit 7400 Integrated Circuit ID301 24 Volt , 40 mA Incandescent Lamp MPS3702, MPS3703, MPS6518 PNP Transistor...
  • Page 80 Part List: Figure 8.10 Morse Character Generator 10 µF, 16 Volt Electrolytic Capacitor 470 Ω, ¼ Watt Resistor 330 Ω, ¼ Watt Resistor P301 1.5 kΩ, Reverse-Log. Taper Potentiometer 7402 Integrated Circuit I12, I19, I32 7404 Integrated Circuit 7410 Integrated Circuit I15, I22 7474 Integrated Circuit 7400 Integrated Circuit...
  • Page 82 Parts List: Figure 8.11: Morse Output Control 2.2 µF, 16 Volt Electrolytic Capacitor C17A 4.7 µF, 25 Volt Electrolytic Capacitor C302, C303 0.001 µF Disc Ceramic Capacitor C304 10 µF, 16 Volt Electrolytic Capacitor R39, R42, R43B, R43C 100 Ω, ¼ Watt Resistor 390 Ω, ¼...
  • Page 84 Parts List: Figure 8.12: Quick Brown Fox Generator and ID Control 0.1 µF Disc Ceramic Capacitor 47 µF, 16 Volt Electrolytic Capacitor C19 - C21 0.01 µF Disc Ceramic Capacitor C19A 0.001 µF Disc Ceramic Capacitor R44 - R50 10 kΩ, ¼ Watt Resistor 1 kΩ, ¼...
  • Page 86 Part List: Figure 8.13: Identifier C20A 0.001 µF Disc Ceramic Capacitor I40, I42 7442 Integrated Circuit 7404 Integrated Circuit 7493 Integrated Circuit 7402 Integrated Circuit JPR5 Jumper, #28 Insulated Wire, 1" long...
  • Page 88 Part List: Figure 8.14: Three-Character Sequencer C21A, C22A 0.001 µF Disc Ceramic Capacitor 7404 Integrated Circuit 7420 Integrated Circuit I45, 147 7401 Integrated Circuit I46, I48 7473 Integrated Circuit 7400 Integrated Circuit 7402 Integrated Circuit...
  • Page 90 Part List: Figure 8.15: Power Supply Module C201, C210 220 µF, 16 Volt Electrolytic Capacitor C202, C204, C208, C209 0.01 µF Disc Ceramic Capacitor C203 0.001 µF Disc Ceramic Capacitor C205 4700 µF, 16 Volt Electrolytic Capacitor C206, C207 1000 µF, 16 Volt Electrolytic Capacitor C208 47 µF, 16 Volt Electrolytic Capacitor C305, C306...

  • Page 96: Extended Memory Option

    EXTENDED MEMORY OPTION FOR THE DKB - 2010 KEYBOARD INSTRUCTION MANUAL...

  • Page 97: Introduction

    HAL DKB-2010 EXTENDED MEMORY OPTION Introduction The HAL 64/128 Key Buffer option extends the memory capacity of the DKB-2010 Dual Mode Keyboard to 64 or 128 keystrokes, depending on the model chosen. With the buffer installed, the operator is free to type for an extended period at a rate greater than the keyboard transmission speed without losing characters.

  • Page 98: Operating Instructions

    7th Reinstall the bottom plate, sliding the front edge beneath the front lip of the cabinet. Fasten it in place with the original screws. The keyboard and buffer are now ready to operate. Refer to Section 3 for instructions on the use of the buffer.

  • Page 99: Theory Of Operation

    Theory of Operation The buffer memory is installed in the DKB-2010 keyboard between the output of the keyencoder and the input of the circuit board. In the standard keyboard, keystrokes are translated into a seven-bit ASCII code by the keyencoder. These codes are fed directly to the ROM, where they are converted to the correct bit pattern for either Morse or RTTY transmission, depending on the mode selected The heart of the buffer is an eight-bit parallel first-in, first-out (FIFO) buffer.

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