--- main/pbx.c	2009-12-01 19:14:31.000000000 -0200
+++ main/pbx.c	2010-01-22 15:23:46.000000000 -0200
@@ -1940,8 +1940,9 @@
 		return AST_EXTENSION_ONHOLD;
 	case AST_DEVICE_BUSY:
 		return AST_EXTENSION_BUSY;
-	case AST_DEVICE_UNAVAILABLE:
 	case AST_DEVICE_UNKNOWN:
+		return AST_EXTENSION_NOT_INUSE;
+	case AST_DEVICE_UNAVAILABLE:
 	case AST_DEVICE_INVALID:
 		return AST_EXTENSION_UNAVAILABLE;
 	case AST_DEVICE_RINGINUSE: