# File lib/network/protocol/terminalfilter.rb, line 392
  def execute(b)
    case b
    when ENQ, SO, SI, DC1, DC3 # not handled
# ENQ  Transmit ANSWERBACK message
# SO   Switch to G1 character set
# SI   Switch to G0 character set
# DC1  Causes terminal to resume transmission (XON).
# DC3  Causes terminal to stop transmitting all codes except XOFF and XON (XOFF).
      ""
    when VT, FF
      "[UP 1]"
    when TAB
      log.debug("(#{@pstack.conn.object_id}) TAB found")
      "[TAB]"
    when BEL
      "[BELL]"
    else
      ""
    end
  end