diff --git a/cf/otp.m4 b/cf/otp.m4
new file mode 100644
index 000000000..ea199367e
--- /dev/null
+++ b/cf/otp.m4
@@ -0,0 +1,27 @@
+dnl $Id$
+dnl
+dnl check requirements for OTP library
+dnl
+AC_DEFUN([rk_OTP],[
+AC_REQUIRE([rk_DB])dnl
+AC_ARG_ENABLE(otp,
+	AC_HELP_STRING([--disable-otp],[if you don't want OTP support]))
+if test "$enable_otp" = yes -a "$ac_cv_func_dbm_firstkey" != yes; then
+	AC_MSG_ERROR([OTP requires a NDBM compatible library])
+fi
+if test "$enable_otp" != no; then
+	if test "$ac_cv_func_dbm_firstkey" = yes; then
+		enable_otp=yes
+	else
+		enable_otp=no
+	fi
+fi
+if test "$enable_otp" = yes; then
+	AC_DEFINE(OTP, 1, [Define if you want OTP support in applications.])
+	LIB_otp='$(top_builddir)/lib/otp/libotp.la'
+	AC_SUBST(LIB_otp)
+fi
+AC_MSG_CHECKING([whether to enable OTP library])
+AC_MSG_RESULT($enable_otp)
+AM_CONDITIONAL(OTP, test "$enable_otp" = yes)dnl
+])