The response to line or response to char statement lets you respond to remote or local applications, or to the keyboard. You specify the response to line or response to char statement in a response definition that is invoked when ESL recognizes text.  The text might be entered by the user on the keyboard or sent to ESL by an application program.

You should specify response to line rather than response to char whenever possible to increase processing efficiency.  Use response to char when ESL needs to respond to data that does not end with the newline character.