ComCarrier()

         Determines if Carrier flag is on

    Syntax:

         ComCarrier() -> lCarrier

    Description:

         Determines if Carrier flag is active. This flag must be specially
         looked out for transmissions or receptions to confirm that the
         interlocutor holds on line with the system.
         If there's a carrier lost, could indicate that the other hand of
         the communication has disconnected.

    Return:

         .T. if Carrier flag is on and .F. if not.

    Example:

         If ! ComCarrier()
           Warning( "NO CARRIER" )
         Else
           Warning( "CARRIER DETECTED" )
         EndIf