diff --git a/src/PacketSerial.h b/src/PacketSerial.h
index 67de570..02daca5 100644
--- a/src/PacketSerial.h
+++ b/src/PacketSerial.h
@@ -84,11 +84,13 @@ class PacketSerial_
     /// \sa https://www.arduino.cc/en/Serial/Begin
     void begin(unsigned long speed)
     {
+        #if !defined(NO_GLOBAL_SERIAL)
         Serial.begin(speed);
         #if ARDUINO >= 100 && !defined(CORE_TEENSY)
         while (!Serial) {;}
         #endif
         setStream(&Serial);
+        #endif
     }
 
     /// \brief Deprecated. Use setStream() to configure a non-default port.