Procedure NTOPN (
	lun: Integer;
	efn: Event_flag;
	links: integer;
	wait_recover: integer;
	VAR IOSB: IO_Status_block
	);
   EXTERNAL;
{*USER*
 
 Must be the first network call (other than NTCONB) issued by a task.
Establishes the task as an active network task.
 LUN specifies the network mailbox lun, which will receive all network
messages (as opposed to network data) for all links for this task.
 EFN will be set when the OPN$ call completes.
 LINKS sets the maximum number of simultaneous links for the task. DECnet
will reject connect requests which would exceed LINKS without notifying
the task. Specify zero (0) for NO limit on the links.
 WAIT_RECOVER specifies the number of minutes (0..32767.) for DECnet to
wait after physical link loss before aborting the logical links. Normally,
a small value (< 5 min. ) will suffice. A value of zero specifies that
the logical link(s) are to be aborted 'immediately' upon physical link
loss.
 }