diff --git a/src/class/cdc/cdc_device.h b/src/class/cdc/cdc_device.h
index 145381c42..1d7a64827 100644
--- a/src/class/cdc/cdc_device.h
+++ b/src/class/cdc/cdc_device.h
@@ -43,6 +43,10 @@
   #define CFG_TUD_CDC_EP_BUFSIZE    (TUD_OPT_HIGH_SPEED ? 512 : 64)
 #endif
 
+#ifndef CFG_TUD_CDC_CLEAR_AT_CONNECTION
+  #define CFG_TUD_CDC_CLEAR_AT_CONNECTION   0
+#endif
+
 #ifdef __cplusplus
  extern "C" {
 #endif