CDON() (BOOLEAN)

 Function
  Determine if carrier detect is on or not.

 Syntax
  CDON()   No arguments are required

 Return Type & Value
  BOOLEAN
  Returns a boolean TRUE if carrier detect is on, FALSE otherwise.

 Remarks
  If you have used CDCHKOFF to turn off automatic carrier detect checking
  PCBoard will not automatically detect and act on a carrier loss.  If
  necessary, this function can be used to detect a carrier loss condition
  and act appropriately.

 Examples
  IF (!CDON()) THEN
    LOG "Carrier lost in PPE "+PPENAME(),FALSE
    HANGUP
  ENDIF