diff --git a/TinyGsmClient.h b/TinyGsmClient.h
index ed3b88c..7c704d6 100644
--- a/TinyGsmClient.h
+++ b/TinyGsmClient.h
@@ -9,35 +9,6 @@
 #ifndef TinyGsmClient_h
 #define TinyGsmClient_h
 
-#if defined(SPARK) || defined(PARTICLE)
-    #include "Particle.h"
-#elif defined(ARDUINO)
-    #if ARDUINO >= 100
-        #include "Arduino.h"
-    #else
-        #include "WProgram.h"
-    #endif
-#endif
-
-#include <Client.h>
-#include <TinyGsmFifo.h>
-
-#ifndef TINY_GSM_YIELD
-  #define TINY_GSM_YIELD() { delay(0); }
-#endif
-
-#if defined(__AVR__)
-  #define TINY_GSM_PROGMEM PROGMEM
-  typedef const __FlashStringHelper* GsmConstStr;
-  #define GFP(x) (reinterpret_cast<GsmConstStr>(x))
-  #define GF(x)  F(x)
-#else
-  #define TINY_GSM_PROGMEM
-  typedef const char* GsmConstStr;
-  #define GFP(x) x
-  #define GF(x)  x
-#endif
-
 #if   defined(TINY_GSM_MODEM_SIM800) || defined(TINY_GSM_MODEM_SIM900)
   #include <TinyGsmClientSIM800.h>
 #elif defined(TINY_GSM_MODEM_M590)
diff --git a/TinyGsmClientM590.h b/TinyGsmClientM590.h
index e857d78..a06e2f6 100644
--- a/TinyGsmClientM590.h
+++ b/TinyGsmClientM590.h
@@ -10,12 +10,13 @@
 #define TinyGsmClientM590_h
 
 //#define GSM_DEBUG Serial
-//#define GSM_USE_HEX
 
 #if !defined(TINY_GSM_RX_BUFFER)
   #define TINY_GSM_RX_BUFFER 256
 #endif
 
+#include <TinyGsmCommon.h>
+
 #define GSM_NL "\r\n"
 static const char GSM_OK[] TINY_GSM_PROGMEM = "OK" GSM_NL;
 static const char GSM_ERROR[] TINY_GSM_PROGMEM = "ERROR" GSM_NL;
@@ -39,22 +40,6 @@ enum RegStatus {
 class TinyGsm
 {
 
-#ifdef GSM_DEBUG
-  template<typename T>
-  static void DBG(T last) {
-    GSM_DEBUG.println(last);
-  }
-
-  template<typename T, typename... Args>
-  static void DBG(T head, Args... tail) {
-    GSM_DEBUG.print(head);
-    GSM_DEBUG.print(' ');
-    DBG(tail...);
-  }
-#else
-  #define DBG(...)
-#endif
-
 public:
   TinyGsm(Stream& stream)
     : stream(stream)
diff --git a/TinyGsmClientSIM800.h b/TinyGsmClientSIM800.h
index 848ed1a..658ff76 100644
--- a/TinyGsmClientSIM800.h
+++ b/TinyGsmClientSIM800.h
@@ -16,6 +16,8 @@
   #define TINY_GSM_RX_BUFFER 64
 #endif
 
+#include <TinyGsmCommon.h>
+
 #define GSM_NL "\r\n"
 static const char GSM_OK[] TINY_GSM_PROGMEM = "OK" GSM_NL;
 static const char GSM_ERROR[] TINY_GSM_PROGMEM = "ERROR" GSM_NL;
@@ -39,22 +41,6 @@ enum RegStatus {
 class TinyGsm
 {
 
-#ifdef GSM_DEBUG
-  template<typename T>
-  static void DBG(T last) {
-    GSM_DEBUG.println(last);
-  }
-
-  template<typename T, typename... Args>
-  static void DBG(T head, Args... tail) {
-    GSM_DEBUG.print(head);
-    GSM_DEBUG.print(' ');
-    DBG(tail...);
-  }
-#else
-  #define DBG(...)
-#endif
-
 public:
   TinyGsm(Stream& stream)
     : stream(stream)
diff --git a/TinyGsmCommon.h b/TinyGsmCommon.h
new file mode 100644
index 0000000..7455274
--- /dev/null
+++ b/TinyGsmCommon.h
@@ -0,0 +1,59 @@
+/**
+ * @file       TinyGsmCommon.h
+ * @author     Volodymyr Shymanskyy
+ * @license    LGPL-3.0
+ * @copyright  Copyright (c) 2016 Volodymyr Shymanskyy
+ * @date       Nov 2016
+ */
+
+#ifndef TinyGsmCommon_h
+#define TinyGsmCommon_h
+
+#if defined(SPARK) || defined(PARTICLE)
+  #include "Particle.h"
+#elif defined(ARDUINO)
+  #if ARDUINO >= 100
+    #include "Arduino.h"
+  #else
+    #include "WProgram.h"
+  #endif
+#endif
+
+#include <Client.h>
+#include <TinyGsmFifo.h>
+
+#ifndef TINY_GSM_YIELD
+  #define TINY_GSM_YIELD() { delay(0); }
+#endif
+
+#if defined(__AVR__)
+  #define TINY_GSM_PROGMEM PROGMEM
+  typedef const __FlashStringHelper* GsmConstStr;
+  #define GFP(x) (reinterpret_cast<GsmConstStr>(x))
+  #define GF(x)  F(x)
+#else
+  #define TINY_GSM_PROGMEM
+  typedef const char* GsmConstStr;
+  #define GFP(x) x
+  #define GF(x)  x
+#endif
+
+#ifdef GSM_DEBUG
+namespace {
+  template<typename T>
+  static void DBG(T last) {
+    GSM_DEBUG.println(last);
+  }
+
+  template<typename T, typename... Args>
+  static void DBG(T head, Args... tail) {
+    GSM_DEBUG.print(head);
+    GSM_DEBUG.print(' ');
+    DBG(tail...);
+  }
+}
+#else
+  #define DBG(...)
+#endif
+
+#endif
diff --git a/TinyWiFiClientESP8266.h b/TinyWiFiClientESP8266.h
index 7430cce..4ac9ea3 100644
--- a/TinyWiFiClientESP8266.h
+++ b/TinyWiFiClientESP8266.h
@@ -10,12 +10,13 @@
 #define TinyWiFiClientESP8266_h
 
 //#define GSM_DEBUG Serial
-//#define GSM_USE_HEX
 
 #if !defined(TINY_GSM_RX_BUFFER)
   #define TINY_GSM_RX_BUFFER 256
 #endif
 
+#include <TinyGsmCommon.h>
+
 #define GSM_NL "\r\n"
 static const char GSM_OK[] TINY_GSM_PROGMEM = "OK" GSM_NL;
 static const char GSM_ERROR[] TINY_GSM_PROGMEM = "ERROR" GSM_NL;
@@ -23,22 +24,6 @@ static const char GSM_ERROR[] TINY_GSM_PROGMEM = "ERROR" GSM_NL;
 class TinyGsm
 {
 
-#ifdef GSM_DEBUG
-  template<typename T>
-  static void DBG(T last) {
-    GSM_DEBUG.println(last);
-  }
-
-  template<typename T, typename... Args>
-  static void DBG(T head, Args... tail) {
-    GSM_DEBUG.print(head);
-    GSM_DEBUG.print(' ');
-    DBG(tail...);
-  }
-#else
-  #define DBG(...)
-#endif
-
 public:
   TinyGsm(Stream& stream)
     : stream(stream)