The character filter is a major feature of NuMorse. It allows you to specify exactly what characters will be played as code. Only the characters displayed in red in the filter grid will be sounded as code. You can switch individual characters on or off by clicking on them. There also some shortcut methods for switching entire groups of characters. To switch a character group first select the ones you need from the preset filters group, then click the Add button to see the selected characters "light up in red". You can use any combination of presets.
The Remove button deletes filter settings as selected by the preset options. It is possible to delete all of the filter characters. If you do this you will get an error message when you attempt to play Morse code.
Some features in NuMorse record your performance . If performance statistics have been gathered then you can use them to switch on those characters that have been recorded as incorrectly typed. This is a useful way to get extra practice with your problem characters. Set how many of your worst characters should be used, then click on the Stats button to get them switched on in the filter. Note: For this feature to work you must have statistics for a previous code drill displayed.
The random group length is used to determine the size of character groups when the program is sending random characters. Groups of five are commonly used, but you can choose any size up to nine or even select random length groups.