diff --git a/PDP10/kl10_dn.c b/PDP10/kl10_dn.c
index 0283be0..255339b 100644
--- a/PDP10/kl10_dn.c
+++ b/PDP10/kl10_dn.c
@@ -280,7 +280,7 @@ DEVICE dn_dev = {
     "DN", dn_unit, dn_reg, dn_mod,
     3, 10, 31, 1, 8, 8,
     NULL, NULL, &dn_reset,
-    NULL, NULL, NULL, &dn_dib, DEV_DEBUG, 0, dev_debug,
+    NULL, NULL, NULL, &dn_dib, DEV_DIS | DEV_DISABLE | DEV_DEBUG, 0, dev_debug,
     NULL, NULL, &dn_help, NULL, NULL, &dn_description
     };