Hooking up to a Code Oscillator or Transmitter

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Parallel port pinouts.


You can use NuMorse Pro to drive a code oscillator or a transmitter via a hardware port. You can either add an extra port as an ISA or PCI card or use the existing printer port on your system. Here are the data pinout details for a Centronics parallel printer port, this view is looking into the rear of the PC.







Bit 0


Bit 1


Bit 2


Bit 3


Bit 4


Bit 5


Bit 6


Bit 7




Here is a circuit diagram of a simple code oscillator that has been tested with NuMorse Pro on the printer port (decimal 888) by the author:




Connect it to your PC between GND and any printer data pin. On a Centronics parallel printer port this would be between pin 33 and any other pin in the table above.


A more advanced circuit for a Relay Interface unit is shown here which drives a flashing mains lamp display. This could be used in a classroom situation for people learning visual signalling methods. Both of the circuits shown here can easily be adapted for serial or parallel port operation.


Serial port pinouts.


9-pin or 25-pin connectors are used for the serial ports on most PCs. If a serial connector is not provided on the PC then it may be possible to use a USB-serial interface unit. Pinout details for the RTS and DTR lines are shown below.


RS-232 - DB9 serial male connector





Pin Assignments for DB9 serial connector


    1     DCD     Data carrier (line signal) detect

    2     RXD     Receive data

    3     TXD      Transmitted data

   4     DTR     Data terminal ready

    5     GND     (Signal) ground

    6     DSR     Data set ready

    7     RTS     Ready/request to send

    8     CTS     Clear to send

    9     RI         Ring indicator


RS-232 - DB25 serial male connector




Pin Assignments for DB25 serial connector


   1                 Shield - chassis/frame protective ground

    2     TXD      Transmitted data

    3     RXD     Receive data

    4     RTS     Ready/request to send

    5     CTS     Clear to send

    6     DSR     Data set ready

    7     GND     (Signal) ground

    8     DCD     Data carrier (line signal) detect

    9                 Reserved for testing - positive voltage

    10               Reserved for testing - negative voltage

    11               Unassigned

    12   SCF     Secondary received carrier (line signal) detect

    13   SCB     Secondary clear to send

    14   SBA     Secondary transmitted data

    15   DB       Transmission signal element timing (clock)

    16   SBB     Secondary received data

    17   DD       Receiver signal element timing (clock)

    18               Unassigned

    19   SCA     Secondary request to send

    20   DTR     Data terminal ready

    21   CG       Signal quality detector

    22   RI         Ring indicator

    23   CH/CI   Data signal rate selector

    24   DA       External transmit signal element timing (clock)

    25               Test mode