diff --git a/libraries/FastSerial/BetterStream.cpp b/libraries/FastSerial/BetterStream.cpp
index a12c3902dc..38e12fa7a9 100644
--- a/libraries/FastSerial/BetterStream.cpp
+++ b/libraries/FastSerial/BetterStream.cpp
@@ -12,6 +12,7 @@
 // Enhancements to the Arduino Stream class.
 //
 
+#include <limits.h>
 #include "BetterStream.h"
 
 // Stream extensions////////////////////////////////////////////////////////////
@@ -52,3 +53,9 @@ BetterStream::_printf_P(const prog_char *fmt, ...)
         va_end(ap);
 }
 
+int
+BetterStream::space(void)
+{
+        // by default claim that there is always space
+        return(INT_MAX);
+}
diff --git a/libraries/FastSerial/BetterStream.h b/libraries/FastSerial/BetterStream.h
index e9b16a00d0..d782a0966e 100644
--- a/libraries/FastSerial/BetterStream.h
+++ b/libraries/FastSerial/BetterStream.h
@@ -28,6 +28,8 @@ public:
         void            _printf_P(const prog_char *, ...);
                 __attribute__ ((format(__printf__, 2, 3)));
 
+        virtual int     space(void);
+
 #define printf_P(fmt, ...) _printf_P((const prog_char *)fmt, ## __VA_ARGS__)
 
 private:
diff --git a/libraries/FastSerial/FastSerial.cpp b/libraries/FastSerial/FastSerial.cpp
index 3e91a2f2da..3368ca1c51 100644
--- a/libraries/FastSerial/FastSerial.cpp
+++ b/libraries/FastSerial/FastSerial.cpp
@@ -142,6 +142,13 @@ int FastSerial::available(void)
 	return ((_rxBuffer->head - _rxBuffer->tail) & _rxBuffer->mask);
 }
 
+int FastSerial::space(void)
+{
+	if (!_open)
+		return (-1);
+	return (((_rxBuffer->tail - _rxBuffer->head) & _rxBuffer->mask) - 1);
+}
+
 int FastSerial::read(void)
 {
 	uint8_t c;
diff --git a/libraries/FastSerial/FastSerial.h b/libraries/FastSerial/FastSerial.h
index 267372c138..9f008bb962 100644
--- a/libraries/FastSerial/FastSerial.h
+++ b/libraries/FastSerial/FastSerial.h
@@ -110,6 +110,7 @@ public:
 	virtual void begin(long baud);
 	virtual void end(void);
 	virtual int available(void);
+	virtual int space(void);
 	virtual int read(void);
 	virtual int peek(void);
 	virtual void flush(void);