diff --git a/CMakeLists.txt b/CMakeLists.txt
index 31009701..ce15d5ca 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -22,7 +22,7 @@ INCLUDE(UseDoxygen)
 SET(LIBNFC_DEBUG_OUTPUT OFF CACHE BOOL "Debug output of communication with the NFC chip")
 SET(LIBNFC_PCSC ON CACHE BOOL "Enable PC/SC support (ACR122)")
 SET(LIBNFC_USB ON CACHE BOOL "Enable direct USB communication support (PN531 and PN533)")
-SET(LIBNFC_DISABLE_SERIAL_AUTOPROBE OFF CACHE BOOL "Disable serial autoprobe")
+SET(LIBNFC_SERIAL_AUTOPROBE_ENABLED OFF CACHE BOOL "Allow serial ports to be probed (can seriously disturb connected serial devices)")
 
 IF(DEFINED CMAKE_INSTALL_LIBDIR)
   SET(libdir ${CMAKE_INSTALL_LIBDIR})
@@ -42,9 +42,9 @@ IF(NOT DEFINED SHARE_INSTALL_PREFIX)
   SET(SHARE_INSTALL_PREFIX share)
 ENDIF(NOT DEFINED SHARE_INSTALL_PREFIX)
 
-IF(LIBNFC_DISABLE_SERIAL_AUTOPROBE)
-  ADD_DEFINITIONS("-DDISABLE_SERIAL_AUTOPROBE")
-ENDIF(LIBNFC_DISABLE_SERIAL_AUTOPROBE)
+IF(LIBNFC_SERIAL_AUTOPROBE_ENABLED)
+  ADD_DEFINITIONS("-DSERIAL_AUTOPROBE_ENABLED")
+ENDIF(LIBNFC_SERIAL_AUTOPROBE_ENABLED)
 
 IF(LIBNFC_DEBUG_OUTPUT)
   ADD_DEFINITIONS(-DDEBUG -g3)
diff --git a/configure.ac b/configure.ac
index 35f4c17b..2862b470 100644
--- a/configure.ac
+++ b/configure.ac
@@ -58,15 +58,15 @@ then
 fi
 AC_SUBST([DEBUG_CFLAGS])
 
-# Serial autoprobing support (default:yes)
-AC_ARG_ENABLE([serial-autoprobe],AS_HELP_STRING([--disable-serial-autoprobe],[Disable serial autoprobing]),[enable_serial_autoprobe=$enableval],[enable_serial_autoprobe="yes"])
+# Serial autoprobing support (default:no)
+AC_ARG_ENABLE([serial-autoprobe],AS_HELP_STRING([--enable-serial-autoprobe],[Allow serial ports to be probed (can seriously disturb connected serial devices)]),[enable_serial_autoprobe=$enableval],[enable_serial_autoprobe="no"])
  
 AC_MSG_CHECKING(for serial autoprobe flag)
 AC_MSG_RESULT($enable_serial_autoprobe)
 
-if test x"$enable_serial_autoprobe" = "xno"
+if test x"$enable_serial_autoprobe" = "xyes"
 then
-  CFLAGS="$CFLAGS -DDISABLE_SERIAL_AUTOPROBE"
+  CFLAGS="$CFLAGS -DSERIAL_AUTOPROBE_ENABLED"
 fi
 
 # PCSC-lite support (default: yes)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index bfb6e05d..9ecb1a2a 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -2,9 +2,9 @@ IF(LIBNFC_VERBOSE_OUTPUT)
   ADD_DEFINITIONS("-DDEBUG")
 ENDIF(LIBNFC_VERBOSE_OUTPUT)
 
-IF(LIBNFC_DISABLE_SERIAL_AUTOPROBE)
-  ADD_DEFINITIONS("-DDISABLE_SERIAL_AUTOPROBE")
-ENDIF(LIBNFC_DISABLE_SERIAL_AUTOPROBE)
+IF(LIBNFC_SERIAL_AUTOPROBE_ENABLED)
+  ADD_DEFINITIONS("-DSERIAL_AUTOPROBE_ENABLED")
+ENDIF(LIBNFC_SERIAL_AUTOPROBE_ENABLED)
 
 IF(LIBNFC_LANG_C99 AND NOT MSVC)
   SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99")
diff --git a/src/lib/drivers/arygon.c b/src/lib/drivers/arygon.c
index 09c372cb..b93b0098 100644
--- a/src/lib/drivers/arygon.c
+++ b/src/lib/drivers/arygon.c
@@ -95,10 +95,10 @@ nfc_device_t* arygon_connect(const nfc_device_desc_t* pndd)
   nfc_device_t* pnd = NULL;
 
   if( pndd == NULL ) {
-#ifdef DISABLE_SERIAL_AUTOPROBE
+#ifndef SERIAL_AUTOPROBE_ENABLED
     INFO("Sorry, serial auto-probing have been disabled at compile time.");
     return NULL;
-#else
+#else /* SERIAL_AUTOPROBE_ENABLED */
     DBG("Trying to find ARYGON device on serial port: %s# at %d bauds.",SERIAL_STRING, SERIAL_DEFAULT_PORT_SPEED);
     // I have no idea how MAC OS X deals with multiple devices, so a quick workaround
     for (uiDevNr=0; uiDevNr<DRIVERS_MAX_DEVICES; uiDevNr++)
@@ -120,7 +120,8 @@ nfc_device_t* arygon_connect(const nfc_device_desc_t* pndd)
       if (sp == CLAIMED_SERIAL_PORT) DBG("Serial port already claimed: %s",acConnect);
 #endif /* DEBUG */
     }
-#endif
+#endif /* SERIAL_AUTOPROBE_ENABLED */
+
     // Test if we have found a device
     if (uiDevNr == DRIVERS_MAX_DEVICES) return NULL;
   } else {
diff --git a/src/lib/drivers/pn532_uart.c b/src/lib/drivers/pn532_uart.c
index 1b12ecf0..ce93ec8a 100644
--- a/src/lib/drivers/pn532_uart.c
+++ b/src/lib/drivers/pn532_uart.c
@@ -96,10 +96,10 @@ pn532_uart_list_devices(nfc_device_desc_t pnddDevices[], size_t szDevices, size_
  * have serious problem with other device on this bus */
   *pszDeviceFound = 0;
 
-#ifdef DISABLE_SERIAL_AUTOPROBE
+#ifndef SERIAL_AUTOPROBE_ENABLED
   INFO("Sorry, serial auto-probing have been disabled at compile time.");
   return false;
-#else /* DISABLE_SERIAL_AUTOPROBE */
+#else /* SERIAL_AUTOPROBE_ENABLED */
 
   // I have no idea how MAC OS X deals with multiple devices, so a quick workaround
   for (iDevice=0; iDevice<DRIVERS_MAX_DEVICES; iDevice++)
@@ -134,7 +134,7 @@ pn532_uart_list_devices(nfc_device_desc_t pnddDevices[], size_t szDevices, size_
     if (sp == CLAIMED_SERIAL_PORT) DBG("Serial port already claimed: %s",acConnect);
 #endif /* DEBUG */
   }
-#endif
+#endif /* SERIAL_AUTOPROBE_ENABLED */
   return true;
 }