diff --git a/bin/mbus-tcp-raw-send.c b/bin/mbus-tcp-raw-send.c
index 8f58b97..7356573 100644
--- a/bin/mbus-tcp-raw-send.c
+++ b/bin/mbus-tcp-raw-send.c
@@ -90,7 +90,7 @@ main(int argc, char **argv)
         return 1;
     }
 
-    if (strlen(addr_str) == 16)
+    if (mbus_is_secondary_address(addr_str))
     {
         // secondary addressing
         int ret;