diff --git a/lib/libc/gen/getttyent.3 b/lib/libc/gen/getttyent.3
index 973dd2998b7e..18401cd01503 100644
--- a/lib/libc/gen/getttyent.3
+++ b/lib/libc/gen/getttyent.3
@@ -30,7 +30,7 @@
 .\" SUCH DAMAGE.
 .\"
 .\"     from: @(#)getttyent.3	6.7 (Berkeley) 4/19/91
-.\"	$Id: getttyent.3,v 1.3 1994/03/12 06:38:48 cgd Exp $
+.\"	$Id: getttyent.3,v 1.4 1994/03/18 04:14:27 cgd Exp $
 .\"
 .Dd April 19, 1991
 .Dt GETTTYENT 3
@@ -70,6 +70,7 @@ struct ttyent {
 #define	TTY_LOCAL	0x04	/* set 'CLOCAL' on open (dev. specific) */
 #define	TTY_RTSCTS	0x08	/* set 'CRTSCTS' on open (dev. specific) */
 #define	TTY_SOFTCAR	0x10	/* ignore hardware carrier (dev. spec.) */
+#define	TTY_MDMBUF	0x20	/* set 'MDMBUF' on open (dev. specific) */
 	int	ty_status;	/* flag values */
 	int	ty_status;	/* flag values */
 	int	ty_status;	/* flag values */
diff --git a/lib/libc/gen/getttyent.c b/lib/libc/gen/getttyent.c
index 8e3bd004e042..65638db2ae7b 100644
--- a/lib/libc/gen/getttyent.c
+++ b/lib/libc/gen/getttyent.c
@@ -33,7 +33,7 @@
 
 #if defined(LIBC_SCCS) && !defined(lint)
 /*static char *sccsid = "from: @(#)getttyent.c	5.10 (Berkeley) 3/23/91";*/
-static char *rcsid = "$Id: getttyent.c,v 1.5 1994/03/12 06:38:55 cgd Exp $";
+static char *rcsid = "$Id: getttyent.c,v 1.6 1994/03/18 04:14:31 cgd Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <ttyent.h>
@@ -117,6 +117,8 @@ getttyent()
 			tty.ty_status |= TTY_RTSCTS;
 		else if (vcmp(_TTYS_SOFTCAR))
 			tty.ty_status |= TTY_SOFTCAR;
+		else if (vcmp(_TTYS_MDMBUF))
+			tty.ty_status |= TTY_MDMBUF;
 		else
 			break;
 	}