EnableCommNotification( nComDev, hWnd, nInBytes, nOutBytes )-> <lSuccess>
------------------------------------------------------------------------------


 PARAMETER:

  <nComDev>    Specifies the communications device that is posting
               notification messages to the window identified by <hWnd>
               This value is returned by OpenComm()

  <hWnd>       Is the handle that identifies the window whose WM_COMMNOTIFY
               message posting will be enabled or disabled. If it is nil,
               EnableCommNotification disables message posting to the
               current window. 

  <nInBytes>   Indicates the number of bytes the COM driver must write to
               the application's input queue before sending a notification
               message. The message signals the application to read
               information from the input queue. 

  <nOutBytes>  Indicates the minimum number of bytes in the output queue.
               When the number of bytes in the output queue falls below this
               number, the COM driver sends the application a notification
               message,signaling it to write information to the output queue


 RETURNS:

  <lSuccess> is TRUE if the function is successful



 DESCRIPTION:

  The EnableCommNotification function enables or disables WM_COMMNOTIFY
  message posting to the given window. 
  If an application specifies -1 for the <nInBytes> parameter, the
  WM_COMMNOTIFY message is sent to the specified window for CN_EVENT and
  CN_TRANSMIT notifications but not for CN_RECEIVE notifications. If -1 is
  specified for the <nOutBytes> parameter, CN_EVENT and CN_RECEIVE
  notifications are sent but CN_TRANSMIT notifications are not.
  If a timeout occurs before as many bytes as specified by <nOutBytes>
  written to the input queue, a WM_COMMNOTIFY message is sent with the
  CN_RECEIVE flag set.



 SOURCE:  

  SOURCE\WINAPI\COMM.C