diff --git a/src/blecsan.cpp b/src/blecsan.cpp
index d305680e..0806776c 100644
--- a/src/blecsan.cpp
+++ b/src/blecsan.cpp
@@ -6,6 +6,9 @@
 #define BT_BD_ADDR_HEX(addr)                                                   \
   addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]
 
+// checking for CWAs we need this magic bytes:
+static const char cwaMagicBytes[] = "\x03\x03\x6F\xfd";
+
 // local Tag for logging
 static const char TAG[] = "bluetooth";
 
@@ -158,10 +161,19 @@ IRAM_ATTR void gap_callback_handler(esp_gap_ble_cb_event_t event,
       // add this device and show new count total if it was not previously added
       mac_add((uint8_t *)p->scan_rst.bda, p->scan_rst.rssi, MAC_SNIFF_BLE);
 
+#if (COUNT_CWA)
+     // we can call the cwa-functions now
+     // because we use the hashed max-value
+     // done in mac_add()
+
+    // check for CWA-signature
+    if ( 0 == strncmp( (const char*)p->scan_rst.ble_adv, cwaMagicBytes , 4) ) {
+        cwa_mac_add( p->scan_rst.bda);
+   }
+#endif
+
+
       /* to be improved in vendorfilter if:
-      
-
-
       // you can search for elements in the payload using the
       // function esp_ble_resolve_adv_data()
       //