diff --git a/link_test/link_test_send_vertex.py b/link_test/link_test_send_vertex.py
index e486e24c..0b772724 100644
--- a/link_test/link_test_send_vertex.py
+++ b/link_test/link_test_send_vertex.py
@@ -80,7 +80,7 @@ def __init__(self, x, y, sends_per_ts, write_route,
         self.__write_route = write_route
         self.__key = None
         self.__mask = None
-        if not self.__write_route:
+        if self.__write_route:
             self.__key = (self.__x << 24) | (self.__y << 16)
             self.__mask = 0xFFFF0000