diff --git a/Network.cpp b/Network.cpp
index 2efeba5..6dbb7a4 100644
--- a/Network.cpp
+++ b/Network.cpp
@@ -96,7 +96,7 @@ void Network::initialize()
 
 int Network::update()
 {
-    long ts = millis();
+    unsigned long ts = millis();
 
     _device->update();