diff --git a/src/arduino_platform.cpp b/src/arduino_platform.cpp
index 169e653..e561a22 100644
--- a/src/arduino_platform.cpp
+++ b/src/arduino_platform.cpp
@@ -6,9 +6,11 @@
 #include <SPI.h>
 #endif
 
+#ifndef KNX_NO_PRINT
 Stream* ArduinoPlatform::SerialDebug = &Serial;
+#endif
 
-ArduinoPlatform::ArduinoPlatform(HardwareSerial* knxSerial) : _knxSerial(knxSerial)
+ArduinoPlatform::ArduinoPlatform() : _knxSerial(nullptr)
 {
 }
 
@@ -29,7 +31,8 @@ void ArduinoPlatform::fatalError()
 
 void ArduinoPlatform::knxUart( HardwareSerial* serial )
 {
-    closeUart();
+    if (_knxSerial)
+        closeUart();
     _knxSerial = serial;
     setupUart();
 }
diff --git a/src/arduino_platform.h b/src/arduino_platform.h
index 33929da..ddf89b0 100644
--- a/src/arduino_platform.h
+++ b/src/arduino_platform.h
@@ -2,12 +2,10 @@
 
 #include "Arduino.h"
 
-extern Stream& _serialDBG;
-
 class ArduinoPlatform : public Platform
 {
   public:
-    ArduinoPlatform(HardwareSerial* knxSerial);
+    ArduinoPlatform();
 
     // basic stuff
     void fatalError();
@@ -29,7 +27,9 @@ class ArduinoPlatform : public Platform
     void closeSpi() override;
     int readWriteSpi (uint8_t *data, size_t len) override;
 #endif
+#ifndef KNX_NO_PRINT
     static Stream* SerialDebug;
+#endif
 
   protected:
     HardwareSerial* _knxSerial;
diff --git a/src/esp32_platform.cpp b/src/esp32_platform.cpp
index cc902dd..535597c 100644
--- a/src/esp32_platform.cpp
+++ b/src/esp32_platform.cpp
@@ -6,12 +6,11 @@
 
 #include "knx/bits.h"
 
-Esp32Platform::Esp32Platform() : ArduinoPlatform(&Serial1)
-{
-}
-
-Esp32Platform::Esp32Platform(HardwareSerial* s) : ArduinoPlatform(s)
+Esp32Platform::Esp32Platform()
 {
+#ifndef KNX_NO_DEFAULT_UART
+    _knxSerial = &Serial1;
+#endif
 }
 
 uint32_t Esp32Platform::currentIpAddress()
diff --git a/src/esp32_platform.h b/src/esp32_platform.h
index 3c006ba..7faf1c7 100644
--- a/src/esp32_platform.h
+++ b/src/esp32_platform.h
@@ -8,7 +8,6 @@ class Esp32Platform : public ArduinoPlatform
 {
 public:
     Esp32Platform();
-    Esp32Platform(HardwareSerial* s);
 
     // ip stuff
     uint32_t currentIpAddress() override;
diff --git a/src/esp_platform.cpp b/src/esp_platform.cpp
index f453fea..337ce4e 100644
--- a/src/esp_platform.cpp
+++ b/src/esp_platform.cpp
@@ -7,12 +7,11 @@
 
 #include "knx/bits.h"
 
-EspPlatform::EspPlatform() : ArduinoPlatform(&Serial)
-{
-}
-
-EspPlatform::EspPlatform( HardwareSerial* s) : ArduinoPlatform(s)
+EspPlatform::EspPlatform()
 {
+#ifndef KNX_NO_DEFAULT_UART
+    _knxSerial = &Serial;
+#endif
 }
 
 uint32_t EspPlatform::currentIpAddress()
diff --git a/src/esp_platform.h b/src/esp_platform.h
index cd026d8..7aa3383 100644
--- a/src/esp_platform.h
+++ b/src/esp_platform.h
@@ -8,7 +8,6 @@ class EspPlatform : public ArduinoPlatform
 {
   public:
     EspPlatform();
-    EspPlatform(HardwareSerial* s);
 
     // ip stuff
     uint32_t currentIpAddress() override;
diff --git a/src/samd_platform.cpp b/src/samd_platform.cpp
index db94c61..2073fd6 100644
--- a/src/samd_platform.cpp
+++ b/src/samd_platform.cpp
@@ -6,12 +6,11 @@
 #include <Arduino.h>
 #include <FlashAsEEPROM.h>
 
-SamdPlatform::SamdPlatform() : ArduinoPlatform(&Serial1)
-{
-}
-
-SamdPlatform::SamdPlatform( HardwareSerial* s) : ArduinoPlatform(s)
+SamdPlatform::SamdPlatform()
 {
+#ifndef KNX_NO_DEFAULT_UART
+    _knxSerial = &Serial1;
+#endif
 }
 
 void SamdPlatform::restart()
diff --git a/src/samd_platform.h b/src/samd_platform.h
index 6b45c83..ea4d437 100644
--- a/src/samd_platform.h
+++ b/src/samd_platform.h
@@ -8,7 +8,6 @@ class SamdPlatform : public ArduinoPlatform
 {
 public:
     SamdPlatform();
-    SamdPlatform( HardwareSerial* s);
 
     void restart();
     uint8_t* getEepromBuffer(uint16_t size);
diff --git a/src/stm32_platform.cpp b/src/stm32_platform.cpp
index e05ab34..ecd3320 100644
--- a/src/stm32_platform.cpp
+++ b/src/stm32_platform.cpp
@@ -4,12 +4,11 @@
 #include <stm32_eeprom.h>
 #include "knx/bits.h"
 
-Stm32Platform::Stm32Platform() : ArduinoPlatform(&Serial2)
-{
-}
-
-Stm32Platform::Stm32Platform( HardwareSerial* s) : ArduinoPlatform(s)
+Stm32Platform::Stm32Platform()
 {
+#ifndef KNX_NO_DEFAULT_UART
+    _knxSerial = &Serial2;
+#endif
 }
 
 Stm32Platform::~Stm32Platform()
diff --git a/src/stm32_platform.h b/src/stm32_platform.h
index 04870ec..c47a1e1 100644
--- a/src/stm32_platform.h
+++ b/src/stm32_platform.h
@@ -5,7 +5,6 @@ class Stm32Platform : public ArduinoPlatform
 {
 public:
     Stm32Platform();
-    Stm32Platform( HardwareSerial* s);
     ~Stm32Platform();
 
     // basic stuff