;	PBDRV.DOC
;
;	THIS FILE CONTAINS A SET OF FORTRAN CALLABLE SUBROUTINES TO USE
;	LK11 PUSHBUTTON BOX VIA THE PB: DRIVER.
;
;	CALLING PROCEDURES:
;
;		CALL PBATT(LUN,[IOST],[IDS])
;
;			ATTACHES THE PB: UNIT, SPECIFIED BY THE "LUN" ARGUMENT
;			LUN:  LOGICAL UNIT NUMBER
;			IOST: I/O STATUS IN LOW ORDER BYTE (OPTIONAL)
;			IDS:  DIRECTIVE STATUS (OPTIONAL)
;
;		CALL PBDET(LUN,[IOST],[IDS])
;
;			DETACHES THE PB: UNIT.
;			SAME ARGUMENTS AS IN PBATT.
;
;		CALL PBKIL(LUN,[IOST],[IDS])
;
;			KILLS OUTSTANDING I/O ON LOGICAL UNIT NUMBER "LUN".
;			SAME ARGUMENTS AS IN PBATT.
;
;		CALL PBSET(LUN,[IOST],[IDS])
;
;			SET UNIT, ASSIGNED TO "LUN".
;			SAME ARGUMENTS AS IN PBATT.
;
;		CALL PBCLR(LUN,[IOST],[IDS])
;
;			CLEARS UNIT, ASSIGNED TO "LUN".
;			SAME ARGUMENTS AS IN PBATT.
;
;		IF(PBSTAT(LUN,[IOST],[IDS])) GO TO 10
;		OR: CALL PBSTAT(LUN,[IOST],[IDS],[STAT])
;
;			"PBSTAT" IS A LOGICAL FUNCTION AND WILL REFLECT
;			THE STATUS OF THE UNIT SPECIFIED [ON/OFF].
;			IF THE SUBROUTINE IS USED, THE LOGICAL "STAT" WILL
;			CONTAIN THE STATUS.
;			SAME ARGUMENTS AS IN PBATT.
;
;		IF(PBRAL(LUN,[IOST],[IDS])) GO TO 10
;		OR: CALL PBRAL(LUN,[IOST],[IDS],[IVAL])
;
;			"PBRAL" IS AN INTEGER FUNCTION WHICH CONTAINS
;			THE 16 BIT STATUS OF THE LK11.
;			IF THE SUBROUTINE IS USED, "IVAL" REFLECTS THIS
;			STATUS.
;			SAME ARGUMENTS AS IN PBATT.
;
;		CALL PBAST(LUN,IEFN,[AST],[IDS])
;
;			A CALL TO THIS ROUTINE WILL INITIATE AN I/O REQUEST,
;			WHICH WILL BE COMPLETED BY PUSHING THE BUTTON, SPECIFIED
;			BY THE "LUN" ARGUMENT. AT COMPLETION THE EVENTFLAG WILL
;			BE SET AND AN USER SUPPLIED AST ROUTINE WILL BE ENTERED,
;			IF WANTED.
;			THE I/O STATUS WILL BE RETURNED AS ARGUMENT IN THE AST
;			ROUTINE.
;
;			LUN:  LOGICAL UNIT NUMBER
;			IEFN: EVENT FLAG NUMBER
;			AST:  ADDRESS OF AST ROUTINE (OPTIONAL)
;			IDS:  DIRECTIVE STATUS (OPTIONAL)
;