The ewpm command is used to enable characters to be generated at a fast rate, whilst increasing the space between characters to make it easier to receive those characters (often known as the Farnsworth Technique). It is an alias of the effective_wpm command.

For a very thorough explanation of Farnsworth Timing check out A Standard for Morse Timing Using the Farnsworth Technique (pdf) by Jon Bloom, courtesy of The Americal Radio Relay League.

  require "cw"

cw do
  wpm        25
  ewpm       12
  word_count 4

Tags: commands