MorseKOB 3.0


Getting started

When you run the program for the first time after a new version has been posted, the system may warn you that it doesn't recognize the application's digital signature.  You can safely disregard this warning and run the program.

If you don't see the main MorseKOB panel in your browser window, please refer to the Java section below.

  1. Make sure the Circuit Closer box is checked.  The circuit must be closed in order to receive.
  2. Select an active wire by typing its number in the Wire # box, or change the current wire number by clicking on the small up and down arrows next to the number.  Wire #101 is a good first choice, because it's always active.
  3. Click on the Connect button to connect to the wire.  The small box to the right of the wire number turns red, indicating that you're connected.  If there's any activity on the wire, you should hear the clicks of a telegraph sounder coming from your speakers.  If the connect indicator remains white, that means the program is unable to connect to the KOB server.
  4. The IDs of all the stations connected to the wire you connected to appear in the ID list in the upper right part of the KOB window.
  5. The program does its best to decode any Morse that's sent over the wire and displays the text in the code reader area in the upper left part of the window.  If the speed of the incoming code changes abruptly from a fast speed to a much slower speed, the code reader may fail to lock in on the new speed.  To resynchronize the code reader, click the mouse anywhere in the code reader area.
  6. To disconnect from the wire, click on the connect button again.  The connect indicator turns white to show that you're disconnected.

Sending on the keyboard

You can send Morse, either locally or to someone else over the Internet, by typing on the keyboard.

  1. Enter a two-letter office call, your first name, and your location (city or town, and state or province) in the text box just above the Circuit Closer.  This is a courtesy to other operators so they'll know who's on the wire.
  2. Set the desired sending speed in the WPM box.
  3. Uncheck the circuit closer box by clicking on it.  This opens the circuit to enable sending.
  4. Click in keyboard area in the lower left of the KOB window to place the cursor there and type whatever you want to send on the keyboard.  Typeahead is allowed.  The program highlights each character as it's sent.
  5. When you're done typing, wait for the program to finish sending your text and then click on the circuit closer box to close the circuit.

If you prefer, you can toggle the circuit closer open and closed by pressing the Escape key instead of clicking on the Circuit Closer control.


Click on the Options button on the main KOB window to open the options window.  After selecting the desired options, click on the OK button to close the options window.


Use the pull-down menu to select a specific sound card on your computer.

Check the Mute box to silence the speakers.


Use the pull-down menu to select the desired serial port.  The controls in the Port panel are enabled only if you have activated the serial port interface by installing RXTX software on your computer.

Check the Keyer box if you want to connect a keyer paddle to the serial port and use it to simulate a bug.


Use the first pull-down menu to select your mode of operation:

Note: In some situations, to have a new mode setting take effect you will have to restart the program by refreshing the web page.

Use the second pull-down menu to specify whether the code reader and keyboard sender should use American Morse or International (Continental) code.  To avoid confusion, it's recommended that wires 20 through 29 be used for International Morse.


If the WPM setting in the Farnsworth panel is greater than the WPM setting on the main KOB window, the code sender will send characters at the higher speed but insert enough extra space—between characters or words, as desired—so that the overall code speed is maintained at the lower rate.


Code reader: This checkbox enables or disables the code reader.

Show versions: Appends the program version numbers to the IDs displayed in the ID list.

Capture timing: Causes the program to display the timing of sent or received code.  Positive numbers represent marks (in milliseconds) and negative numbers represent spaces.

Connecting external equipment

In order to use MorseKOB with an external key or sounder, you'll need the following:

USB-to-serial adapter

[Add info about recommended adapters (Cables to Go for Windows and Linux, Keyspan for Mac OS X) and how to install the driver software.]

RXTX software

Java itself doesn't provide access to the serial port, so if you want to connect a key or sounder to your computer you'll have to install an RXTX module specific to your operating system.

Once you've installed the RXTX software according to the instructions below, all available serial ports will appear in the pull-down list on the MorseKOB control panel.  Select the one that you're using for your telegraph interface.

An easy way to tell which comm port is associated with a particular USB adapter is to unplug the adapter, note the comm ports that appear in the list, then plug the adapter in again and see which one has been added.  You'll have to restart the program (by refreshing the web page, for example) to update the port list after you connect or disconnect a USB adapter.  This trick doesn't work for the Mac, but the port names are more intuitive on the Mac anyway.

Download the file rxtxSerial.dll (32-bit or 64-bit version) and save it in C:\Windows (or any other location in your system's library search path).

Mac OS
Download the file librxtxSerial.jnilib (32/64-bit combined version) and save it in Macintosh HD/System/Library/Java/Extensions.  To download the file with Safari, Control-click on the link and select Save Linked File As.  Make sure Safari doesn't append a .txt extension to the filename.

Download the file (32-bit or 64-bit version) and save it in /usr/lib (or any other location in your system's library search path).

Known problems


MorseKOB 3.0 is implemented as a Java applet, and in the years since I wrote the program Java has become more and more of a headache, to the point where I have essentially abandoned support for MorseKOB 3.0. If you're running Windows, then you're better off with MorseKOB 2.5. If you're using Linux or macOS, however, then MorseKOB 3.0 may be your only choice. In that case, you'll have to deal with a number of Java issues.

Web browser compatibility

Java applets simply aren't supported by many of the most recent web browsers.  In particular, you can't use Chrome or Edge. It does work with Internet Explorer and Safari.

Once Java is installed (see the following section), you may have to the Java plug-in for your web browser.

Java version

MorseKOB 3.0 requires Java Version 6 or later (also known as version 1.6.0).  If the MorseKOB web page doesn't display the KOB control panel, then visit to see which version of Java is installed on your computer.

Mac users who delete the Apple-supplied Java program and install the latest one from Oracle must delete the old Java preferences file in Macintosh HD/Applications/Utilities, if installation of the Oracle version leaves it in place.

Also, the Java files at the user level are in Macintosh HD/Users/(username)/Library/Oracle/Java. But ordinarily there is no need to access the files in there.

To access the User-level Library folder, click on the desktop to bring the Finder to the front. Hold down the Option key and click on the Go menu. "Library" will then be listed as a choice. For some reason this is the only way to access it in Lion and Mountain Lion.

Java security setting

Most likely Java will complain that the MorseKOB program doesn't meet its security requirements. To fix this, you'll have to do the following:

  1. Launch the Java Control Panel to configure the Java settings.
  2. Select the Security tab.
  3. Click on the Edit Site List button for the exception site list and then click on the Add button.
  4. Enter in the text box.
  5. Click on Add, OK, and OK to accept MorseKOB as a recognized site.


If you have any questions, comments, or suggestions—no matter how trivial or obvious they may seem—I definitely want to hear from you.  I may not be seeing the same thing on my computer and I may not have heard about it from anyone else.  My email address is at the bottom of the MorseKOB home page.

Java console

If you have trouble running the program, I may ask you for a copy of the Java console output.  If you're running Windows, here's how to enable the Java console:

  1. Go to the Windows Control Panel.
  2. Open the Java Control Panel.
  3. Select the Advanced tab.
  4. Click on the + sign next to "Java console".
  5. Click on the "Show console" radio button.
  6. Click on OK to close the Java Control Panel.
  7. Close the Windows Control Panel.

If you're running Mac OS X, do the following:

  1. Go to Applications > Utilities and open Java Preferences
  2. Select the Advanced tab.
  3. Click on the "Show console" radio button.
  4. Quit out of Java Preferences.

Once you've done this, whenever you run MorseKOB a Java console window will open up and display status and diagnostic information for the program. You can copy this data by clicking on the Copy button at the bottom of the window, which you can then insert directly into an email message.

Screen shots

I may also want to see a screen shot of your KOB window.  Here's the procedure for doing that in Windows:

  1. Make sure the KOB window is active by clicking on the window's title bar.
  2. Press Alt-PrintScreen on your keyboard to capture a copy of the window's screen image.
  3. Paste the image into an email message.

On the Mac, press Command-Shift-4 (for a portion of the screen) or Command-Shift-3 (for the entire screen) to save a screen shot to the desktop.  On Linux, use Applications > Accessories > Take Screenshot.

Resetting options

To restore the program's options to their default settings, download and run the program ResetOptions.  This program runs very quickly and without any visible output, so it may appear that it hasn't done anything.  But the next time you run the KOB program, you should find that its settings have reverted to their default state.


Revised 2017-12-20
Les Kerr