struct	consolefontdesc {
	unsigned short		charcount;	/* characters in font (256 or 512) */
	unsigned short		charheight;	/* scan lines per character (1-32) */
	char	*	chardata;	/* font data in expanded form */
};

struct	unimapdesc {
	unsigned short		entry_ct;
	struct unipair	*	entries;
};

struct	unipair {
	unsigned short		unicode;
	unsigned short		fontpos;
};

struct	unimapinit {
	unsigned short		advised_hashsize;	/* 0 if no opinion */
	unsigned short		advised_hashstep;	/* 0 if no opinion */
	unsigned short		advised_hashlevel;	/* 0 if no opinion */
};

struct	kbentry {
	unsigned char		kb_table;
	unsigned char		kb_index;
	unsigned short		kb_value;
};

struct	kbsentry {
	unsigned char		kb_func;
	unsigned char		kb_string[512];
};

struct	kbdiacrs {
	unsigned int		kb_cnt;
	struct kbdiacr		kbdiacr[256];
};

struct	kbdiacr {
	unsigned char		diacr;
	unsigned char		base;
	unsigned char		result;
};

struct	kbkeycode {
	unsigned int		scancode;
	unsigned int		keycode;
};

struct	vt_mode {
	char		mode;	/* vt mode */
	char		waitv;	/* if set, hang on writes if not active */
	short		relsig;	/* signal to raise on release req */
	short		acqsig;	/* signal to raise on acquisition */
	short		frsig;	/* unused (set to 0) */
};

struct	vt_stat {
	unsigned short		v_active;	/* active vt */
	unsigned short		v_signal;	/* signal to send */
	unsigned short		v_state;	/* vt bit mask */
};

struct	vt_sizes {
	unsigned short		v_rows;	/* # rows */
	unsigned short		v_cols;	/* # columns */
	unsigned short		v_scrollsize;	/* no longer used */
};

struct	vt_consize {
	unsigned short		v_rows;	/* number of rows */
	unsigned short		v_cols;	/* number of columns */
	unsigned short		v_vlin;	/* number of pixel rows on screen */
	unsigned short		v_clin;	/* number of pixel rows per character */
	unsigned short		v_vcol;	/* number of pixel columns on screen */
	unsigned short		v_ccol;	/* number of pixel columns per character */
};

struct	{
	char		subcode;
	short		xs,
			ys,
			xe,
			ye;
	short		sel_mode;
};

0:

Screen blanking is disabled.

1:

The current video adapter register settings are saved, then the controller is programmed to turn off the vertical synchronization pulses. This puts the monitor into "standby" mode. If your monitor has an Off_Mode timer, then it will eventually power down by itself.

2:

The current settings are saved, then both the vertical and horizontal synchronization pulses are turned off. This puts the monitor into "off" mode. If your monitor has no Off_Mode timer, or if you want your monitor to power down immediately when the blank_timer times out, then you choose this option. (Caution: Powering down frequently will damage the monitor.) (Since 1.1.76.)