diff --git a/scsh/aix/tty-consts.scm b/scsh/aix/tty-consts.scm
index 036607c..5b7c943 100644
--- a/scsh/aix/tty-consts.scm
+++ b/scsh/aix/tty-consts.scm
@@ -44,7 +44,7 @@
 (define	num-ttychars		16)
 
 ;;; Magic "disable feature" tty character
-(define disable-tty-char (ascii->char #x00))	; _POSIX_VDISABLE
+(define disable-tty-char (ascii->char #xff))	; _POSIX_VDISABLE
 
 ;;; Flags controllling input processing
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;