new file mode 100644
--- /dev/null
+++ b/scripts/control/tzero2.m
@@ -0,0 +1,65 @@
+# Copyright (C) 1993 John W. Eaton
+# 
+# This file is part of Octave.
+# 
+# Octave is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 2, or (at your option) any
+# later version.
+# 
+# Octave is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with Octave; see the file COPYING.  If not, write to the Free
+# Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+
+function zr = tzero2 (a, b, c, d, bal)
+
+# Usage: zr = tzero2 (a, b, c, d, bal)
+#
+# Compute the transmission zeros of a, b, c, d.
+#
+# bal = balancing option (see balance); default is "B".
+#
+# Needs to incorporate mvzero algorithm to isolate finite zeros.
+
+# Written by A. S. Hodel (scotte@eng.auburn.edu) August 1993.
+# $Revision: 1.1.1.1 $
+# $Log$
+
+  if (nargin == 4)
+    bal = "B";
+  elseif (nargin != 5)
+    error ("tzero: illegal number of arguments");
+  endif
+
+  [n, m, p] = abcddim (a, b, c, d);
+
+  if (n > 0 && m > 0 && p > 0)
+    if (m != p)
+      fprintf (stderr, "tzero: number of inputs,outputs differ.  squaring up");
+      if (p > m)
+	fprintf (stderr, "       by padding b and d with zeros.");
+	b = [b, zeros (n, p-m)];
+	d = [d, zeros (p, p-m)];
+	m = p;
+      else
+	fprintf (stderr, "       by padding c and d with zeros.");
+	c = [c; zeros (m-p, n)];
+	d = [d; zeros (m-p, m)];
+	p = m;
+      endif
+      fprintf (stderr, "This is a kludge.  Try again with SISO system.");
+    endif
+    ab = [-a, -b; c, d];
+    bb = [eye (n), zeros (n, m); zeros (p, n), zeros (p, m)];
+    [ab,bb] = balance (ab, bb);
+    zr = -qz (ab, bb);
+  else
+    error ("tzero: a, b, c, d not compatible.  exiting");
+  endif
+
+endfunction