diff --git a/RF24.cpp b/RF24.cpp
index b9606cd..6b8a073 100644
--- a/RF24.cpp
+++ b/RF24.cpp
@@ -11,7 +11,7 @@
 #include "RF24.h"
 #include "nRF24L01.h"
 
-#undef SERIAL_DEBUG
+#define SERIAL_DEBUG
 #ifdef SERIAL_DEBUG
 #define IF_SERIAL_DEBUG(x) (x)
 #else
@@ -51,6 +51,18 @@ uint8_t RF24::read_register(uint8_t reg, uint8_t* buf, uint8_t len)
 
 /******************************************************************/
 
+uint8_t RF24::read_register(uint8_t reg) 
+{
+  csn(LOW);
+  SPI.transfer( R_REGISTER | ( REGISTER_MASK & reg ) );
+  uint8_t result = SPI.transfer(0xff);
+
+  csn(HIGH);
+  return result;
+}
+
+/******************************************************************/
+
 uint8_t RF24::write_register(uint8_t reg, const uint8_t* buf, uint8_t len)
 {
   uint8_t status;
@@ -190,7 +202,7 @@ void RF24::print_observe_tx(uint8_t value)
 /******************************************************************/
 
 RF24::RF24(uint8_t _cepin, uint8_t _cspin): 
-  ce_pin(_cepin), csn_pin(_cspin), payload_size(32)
+  ce_pin(_cepin), csn_pin(_cspin), payload_size(32), ack_packet_available(false)
 {
 }
 
@@ -327,6 +339,7 @@ boolean RF24::write( const void* buf, uint8_t len )
 
   // Transmitter power-up
   write_register(CONFIG, _BV(EN_CRC) | _BV(PWR_UP));
+  delay(2);
 
   // Send the payload
   write_payload( buf, len );
@@ -339,18 +352,37 @@ boolean RF24::write( const void* buf, uint8_t len )
   // Monitor the send
   uint8_t observe_tx;
   uint8_t status;
+  uint8_t retries = 255;
   do
   {
     status = read_register(OBSERVE_TX,&observe_tx,1);
     IF_SERIAL_DEBUG(Serial.print(status,HEX));
     IF_SERIAL_DEBUG(Serial.print(observe_tx,HEX));
+    if ( ! retries-- )
+    {
+      IF_SERIAL_DEBUG(printf("ABORTED: too many retries\n\r"));
+      break;
+    }
   }
   while( ! ( status & ( _BV(TX_DS) | _BV(MAX_RT) ) ) );
 
   if ( status & _BV(TX_DS) )
     result = true;
-
-  IF_SERIAL_DEBUG(Serial.println(result?"...OK.":"...Failed"));
+  
+  IF_SERIAL_DEBUG(Serial.print(result?"...OK.":"...Failed"));
+  
+  ack_packet_available = ( status & _BV(RX_DR) );
+  uint8_t pl_len = 0; 
+  if ( ack_packet_available )
+  {
+    write_register(STATUS,_BV(RX_DR) );
+    csn(LOW);
+    SPI.transfer( R_RX_PL_WID );
+    pl_len = SPI.transfer(0xff);
+    csn(HIGH);
+    IF_SERIAL_DEBUG(Serial.print("[AckPacket]/"));
+    IF_SERIAL_DEBUG(Serial.println(pl_len,DEC));
+  }
 
   // Yay, we are done.
   ce(LOW);
@@ -378,12 +410,11 @@ boolean RF24::available(void)
 boolean RF24::available(uint8_t* pipe_num) 
 {
   uint8_t status = get_status();
+  IF_SERIAL_DEBUG(print_status(status));
   boolean result = ( status & _BV(RX_DR) );
 
   if (result)
   {
-    IF_SERIAL_DEBUG(print_status(status));
-
     // If the caller wants the pipe number, include that
     if ( pipe_num )
       *pipe_num = ( status >> RX_P_NO ) & B111;
@@ -394,6 +425,12 @@ boolean RF24::available(uint8_t* pipe_num)
     // actually READ the payload?
 
     write_register(STATUS,_BV(RX_DR) );
+
+    // Handle ack payload receipt
+    if ( status & _BV(TX_DS) )
+    {
+      write_register(STATUS,_BV(TX_DS));
+    }
   }
 
   return result;
@@ -458,5 +495,67 @@ void RF24::openReadingPipe(uint8_t child, uint64_t value)
     write_register(EN_RXADDR,en_rx);
   }
 }
+
+/******************************************************************/
+  
+void RF24::toggle_features(void)
+{
+  csn(LOW);
+  SPI.transfer( ACTIVATE );
+  SPI.transfer( 0x73 );
+  csn(HIGH);
+}
+
+/******************************************************************/
+
+void RF24::enableAckPayload(void)
+{
+  //
+  // enable ack payload and dynamic payload features
+  //
+
+  write_register(FEATURE,read_register(FEATURE) | _BV(EN_ACK_PAY) | _BV(EN_DPL) );
+
+  // If it didn't work, the features are not enabled
+  if ( ! read_register(FEATURE) )
+  {
+    // So enable them and try again
+    toggle_features();
+    write_register(FEATURE,read_register(FEATURE) | _BV(EN_ACK_PAY) | _BV(EN_DPL) );
+  }
+
+  IF_SERIAL_DEBUG(printf("FEATURE=%i\n\r",read_register(FEATURE)));
+
+  //
+  // Enable dynamic payload on pipe 0
+  //
+
+  write_register(DYNPD,read_register(DYNPD) | _BV(DPL_P1) | _BV(DPL_P0));
+}
+
+/******************************************************************/
+
+void RF24::writeAckPayload(uint8_t pipe, const void* buf, uint8_t len)
+{
+  const uint8_t* current = (const uint8_t*)buf;
+
+  csn(LOW);
+  SPI.transfer( W_ACK_PAYLOAD | ( pipe & B111 ) );
+  uint8_t data_len = min(len,32);
+  while ( data_len-- )
+    SPI.transfer(*current++);
+
+  csn(HIGH);
+}
+
+/******************************************************************/
+
+boolean RF24::isAckPayloadAvailable(void)
+{
+  boolean result = ack_packet_available;
+  ack_packet_available = false;
+  return result;
+}
+
 // vim:ai:cin:sts=2 sw=2 ft=cpp
 
diff --git a/RF24.h b/RF24.h
index 2b2d6b0..d68deac 100644
--- a/RF24.h
+++ b/RF24.h
@@ -21,6 +21,7 @@ private:
   uint8_t ce_pin; /**< "Chip Enable" pin, activates the RX or TX role */
   uint8_t csn_pin; /**< SPI Chip select */
   uint8_t payload_size; /**< Fixed size of payloads */
+  boolean ack_packet_available; /**< Whether there is an ack packet waiting */
 
 protected:  
   /**
@@ -54,6 +55,8 @@ protected:
    * @return Current value of status register
    */
   uint8_t read_register(uint8_t reg, uint8_t* buf, uint8_t len) ;
+  
+  uint8_t read_register(uint8_t reg) ;
 
   /**
    * Write a chunk of data to a register
@@ -95,7 +98,7 @@ protected:
    * @return Current value of status register
    */
   uint8_t read_payload(void* buf, uint8_t len) ;
-
+public:
   /**
    * Empty the receive buffer
    *
@@ -109,7 +112,7 @@ protected:
    * @return Current value of status register
    */
   uint8_t flush_tx(void);
-
+protected:
   /**
    * Retrieve the current status of the chip
    *
@@ -135,6 +138,7 @@ protected:
    */
   void print_observe_tx(uint8_t value) ;
 
+  void toggle_features(void);
   /**@}*/
 
 public:
@@ -299,6 +303,11 @@ public:
    */
   void openReadingPipe(uint8_t number, uint64_t address);
 
+  void enableAckPayload(void);
+
+  void writeAckPayload(uint8_t pipe, const void* buf, uint8_t len);
+
+  boolean isAckPayloadAvailable(void);
 };
 
 /**
diff --git a/examples/pingpair_pl/.gitignore b/examples/pingpair_pl/.gitignore
new file mode 100644
index 0000000..ea1472e
--- /dev/null
+++ b/examples/pingpair_pl/.gitignore
@@ -0,0 +1 @@
+output/
diff --git a/examples/pingpair_pl/makefile b/examples/pingpair_pl/makefile
new file mode 100644
index 0000000..a1c6d4c
--- /dev/null
+++ b/examples/pingpair_pl/makefile
@@ -0,0 +1,290 @@
+# Arduino Makefile
+# Arduino adaptation by mellis, eighthave, oli.keller
+# Modified by Kerry Wong to support NetBeans
+# Modified by Rob Gray (Graynomad) for use with Windows and no IDE
+#   This works in my environment and I use it to program two different 
+#   328-based boards and a Mega2560. It's not necessarily robust and 
+#   I may have broken something in the original file that I don't use.
+#
+# This makefile allows you to build sketches from the command line
+# without the Arduino environment.
+#
+# Instructions for using the makefile:
+#
+#  1. Copy this file into the folder with your sketch. The project code file
+#	  should have a .c extension however the file gets copied to a .cpp before
+#     compilation so you still write in C++.
+#
+#  2. Modify the lines between the double ### rows to set the paths 
+#     comm ports etc for your system. EG. c:/progra~1/arduino/arduino-00
+#     for the Arduino IDE, Note the use of short folder name, don't use
+#     "Program files" because spaces will break the build.
+#
+#     Set the line containing "MCU" to match your board's processor.
+#     Typically ATmega328 or ATmega2560.  If you're using a LilyPad Arduino,
+#     change F_CPU to 8000000.
+#
+#  3. At the command line, change to the directory containing your
+#     program's file and the makefile.
+#
+#  4. Type "make" and press enter to compile/verify your program.
+#     The default make target will also perform the uplode using avrdude.
+#
+#     The first time this is done all required libraries will be built
+#     and a core.a file will be created in the output folder.
+#
+#  NOTES:
+#     All output goes into a folder called "output" underneath the working folder.
+#     The default all: target creates symbol (.sym) and expanded assembly 
+#     (.lss) files and uploads the program.
+#
+#
+##########################################################
+##########################################################
+# Select processor here
+MCU 			= atmega328p
+#MCU 			= atmega2560
+
+ifeq ($(MCU),atmega2560)
+UPLOAD_RATE 	= 115200
+AVRDUDE_PROTOCOL = stk500v2
+COM 			= 39
+endif
+
+ifeq ($(MCU),atmega328p)
+UPLOAD_RATE 	= 57600
+AVRDUDE_PROTOCOL = stk500v1
+COM 			= 33
+endif
+
+UNAME := $(shell uname)
+
+ifeq ($(UNAME),Darwin)
+ARDUINO_VERSION	= 21
+ARDUINO_DIR 	= /opt/arduino-00$(ARDUINO_VERSION)
+AVR_TOOLS_PATH 	= $(ARDUINO_DIR)/hardware/tools/avr/bin
+AVRDUDECONFIG_PATH = $(ARDUINO_DIR)/hardware/tools/avr/etc
+PORT                    = /dev/tty.usbserial-A600eHIs 
+PORT2                   = /dev/tty.usbserial-A9007LmI
+else
+ARDUINO_VERSION	= 22
+ARDUINO_DIR 	= /opt/arduino-00$(ARDUINO_VERSION)
+AVR_TOOLS_PATH 	= /usr/bin
+AVRDUDECONFIG_PATH = $(ARDUINO_DIR)/hardware/tools
+PORT 			= /dev/ttyUSB0
+PORT2 			= /dev/ttyUSB1
+endif
+
+PROJECT_NAME 	= $(notdir $(PWD))
+PROJECT_DIR 	= . 
+ARDUINO_CORE 	= $(ARDUINO_DIR)/hardware/arduino/cores/arduino
+ARDUINO_AVR 	= $(ARDUINO_DIR)/hardware/tools/avr/avr/include/avr
+ARDUINO_LIB 	= $(ARDUINO_DIR)/libraries
+F_CPU 			= 16000000
+
+##########################################################
+##########################################################
+
+# Note that if your program has dependencies other than those
+# already listed below, you will need to add them accordingly.
+C_MODULES =  \
+$(ARDUINO_CORE)/wiring_pulse.c \
+$(ARDUINO_CORE)/wiring_analog.c \
+$(ARDUINO_CORE)/pins_arduino.c \
+$(ARDUINO_CORE)/wiring.c \
+$(ARDUINO_CORE)/wiring_digital.c \
+$(ARDUINO_CORE)/WInterrupts.c \
+$(ARDUINO_CORE)/wiring_shift.c \
+
+CXX_MODULES = \
+$(ARDUINO_CORE)/Tone.cpp \
+$(ARDUINO_CORE)/main.cpp \
+$(ARDUINO_CORE)/WMath.cpp \
+$(ARDUINO_CORE)/Print.cpp \
+$(ARDUINO_CORE)/HardwareSerial.cpp \
+$(ARDUINO_LIB)/SPI/SPI.cpp \
+../../RF24.cpp
+
+CXX_APP 	= output/$(PROJECT_NAME).cpp
+MODULES 	= $(C_MODULES) $(CXX_MODULES)
+SRC 		= $(C_MODULES)
+CXXSRC 		= $(CXX_MODULES) $(CXX_APP)
+FORMAT 		= ihex
+
+# Name of this Makefile (used for "make depend").
+MAKEFILE = Makefile
+
+# Debugging format.
+# Native formats for AVR-GCC's -g are stabs [default], or dwarf-2.
+# AVR (extended) COFF requires stabs, plus an avr-objcopy run.
+#DEBUG = stabs
+DEBUG =
+
+OPT = s
+
+# Place -D or -U options here
+CDEFS = -DF_CPU=$(F_CPU)L -DARDUINO=$(ARDUINO_VERSION)
+CXXDEFS = -DF_CPU=$(F_CPU)L -DARDUINO=$(ARDUINO_VERSION)
+
+# Place -I options here
+CINCS = -I$(ARDUINO_CORE) -I$(ARDUINO_LIB) -I$(PROJECT_DIR) -I$(ARDUINO_AVR) -I$(ARDUINO_LIB)/SPI -I../..
+
+CXXINCS = -I$(ARDUINO_CORE) -I$(ARDUINO_LIB)
+
+# Compiler flag to set the C Standard level.
+# c89   - "ANSI" C
+# gnu89 - c89 plus GCC extensions
+# c99   - ISO C99 standard (not yet fully implemented)
+# gnu99 - c99 plus GCC extensions
+#CSTANDARD = -std=gnu99
+CDEBUG 		= -g$(DEBUG)
+#CWARN 		= -Wall -Wstrict-prototypes
+CWARN 		= -Wall   # show all warnings
+#CWARN 		= -w      # suppress all warnings
+CMAP		= -Wl,-Map,output.map 
+####CTUNING = -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums
+CTUNING = -ffunction-sections -fdata-sections
+CXXTUNING = -fno-exceptions -ffunction-sections -fdata-sections
+#CEXTRA = -Wa,-adhlns=$(<:.c=.lst)
+MMCU 		= -mmcu=$(MCU)
+
+CFLAGS = $(CDEBUG) -O$(OPT) $(CMAP) $(CWARN) $(CTUNING) $(MMCU) $(CDEFS) $(CINCS) $(CSTANDARD) $(CEXTRA)
+CXXFLAGS = $(CDEBUG) -O$(OPT) $(CWARN) $(CXXTUNING) $(CDEFS) $(CINCS)
+#ASFLAGS = -Wa,-adhlns=$(<:.S=.lst),-gstabs
+LDFLAGS = -O$(OPT) -lm -Wl,--gc-sections
+#LDFLAGS = -O$(OPT) -lm -Wl,-Map,output/$(PROJECT_NAME).map 
+
+# Programming support using avrdude. Settings and variables.
+AVRDUDE_PORT = $(PORT)
+AVRDUDE_WRITE_FLASH = -U flash:w:output/$(PROJECT_NAME).hex:i
+
+AVRDUDE_FLAGS = -V -F -D -C $(AVRDUDECONFIG_PATH)/avrdude.conf \
+-p $(MCU) -c $(AVRDUDE_PROTOCOL) -b $(UPLOAD_RATE)
+
+# Program settings
+CC 			= $(AVR_TOOLS_PATH)/avr-gcc
+CXX 		= $(AVR_TOOLS_PATH)/avr-g++
+LD 			= $(AVR_TOOLS_PATH)/avr-gcc
+OBJCOPY 	= $(AVR_TOOLS_PATH)/avr-objcopy
+OBJDUMP 	= $(AVR_TOOLS_PATH)/avr-objdump
+AR 			= $(AVR_TOOLS_PATH)/avr-ar
+SIZE 		= $(AVR_TOOLS_PATH)/avr-size
+NM 			= $(AVR_TOOLS_PATH)/avr-nm
+AVRDUDE 	= $(AVR_TOOLS_PATH)/avrdude
+REMOVE 		= rm -f
+MV 			= mv -f
+
+# Define all object files.
+OBJ = $(SRC:.c=.o) $(CXXSRC:.cpp=.o) $(ASRC:.S=.o)
+OBJ_MODULES = $(C_MODULES:.c=.o) $(CXX_MODULES:.cpp=.o)
+
+# Define all listing files.
+LST = $(ASRC:.S=.lst) $(CXXSRC:.cpp=.lst) $(SRC:.c=.lst)
+
+# Combine all necessary flags and optional flags.
+# Add target processor to flags.
+ALL_CFLAGS 	= $(CFLAGS) -mmcu=$(MCU)
+ALL_CXXFLAGS = $(CXXFLAGS) -mmcu=$(MCU)
+ALL_ASFLAGS = -x assembler-with-cpp $(ASFLAGS) -mmcu=$(MCU)
+ALL_LDFLAGS = $(LDFLAGS) -mmcu=$(MCU)
+
+# Default target.
+# This is th etarget that gets executed with a make command
+# that has no parameters, ie "make".
+all: applet_files build sym lss size upload
+
+build: elf hex
+
+output/$(PROJECT_NAME).cpp: $(PROJECT_NAME).pde
+	test -d output || mkdir output
+	echo "#include <WProgram.h>" > $@ 
+	echo "#line 1 \"$<\"" >> $@ 
+	cat $< >> $@ 
+
+elf: output/$(PROJECT_NAME).elf
+hex: output/$(PROJECT_NAME).hex
+eep: output/$(PROJECT_NAME).eep
+lss: output/$(PROJECT_NAME).lss
+#sym: output/$(PROJECT_NAME).sym
+
+# Upload HEX file to Arduino
+upload: output/$(PROJECT_NAME).hex
+	$(AVRDUDE) $(AVRDUDE_FLAGS) -P $(PORT) $(AVRDUDE_WRITE_FLASH)
+	$(AVRDUDE) $(AVRDUDE_FLAGS) -P $(PORT2) $(AVRDUDE_WRITE_FLASH)
+
+sym:
+	$(NM) -n -C --format=posix output/$(PROJECT_NAME).elf > output/$(PROJECT_NAME).sym
+	
+# Display size of file.
+size:
+	$(SIZE) output/$(PROJECT_NAME).elf
+	
+# Convert ELF to COFF for use in debugging / simulating in AVR Studio or VMLAB.
+COFFCONVERT=$(OBJCOPY) --debugging \
+--change-section-address .data-0x800000 \
+--change-section-address .bss-0x800000 \
+--change-section-address .noinit-0x800000 \
+--change-section-address .eeprom-0x810000
+
+coff: output/$(PROJECT_NAME).elf
+	$(COFFCONVERT) -O coff-avr output/$(PROJECT_NAME).elf $(PROJECT_NAME).cof
+
+	extcoff: $(PROJECT_NAME).elf
+	$(COFFCONVERT) -O coff-ext-avr output/$(PROJECT_NAME).elf $(PROJECT_NAME).cof
+
+.SUFFIXES: .elf .hex .eep .lss .sym
+
+.elf.hex:
+	$(OBJCOPY) -O $(FORMAT) -R .eeprom $< $@
+
+.elf.eep:
+	$(OBJCOPY) -O $(FORMAT) -j .eeprom --set-section-flags=.eeprom="alloc,load" \
+	--no-change-warnings \
+	--change-section-lma .eeprom=0 $< $@
+
+# Create extended listing file from ELF output file.
+.elf.lss:
+	$(OBJDUMP) -h -S $< > $@
+
+# Link: create ELF output file from library.
+#output/$(PROJECT_NAME).elf: $(PROJECT_NAME).c output/core.a
+output/$(PROJECT_NAME).elf: output/$(PROJECT_NAME).o output/core.a
+	$(LD) $(ALL_LDFLAGS) -o $@ output/$(PROJECT_NAME).o output/core.a
+
+output/core.a: $(OBJ_MODULES)
+	@for i in $(OBJ_MODULES); do echo $(AR) rcs output/core.a $$i; $(AR) rcs output/core.a $$i; done
+
+# Compile: create object files from C++ source files.
+.cpp.o:
+	$(CXX) -c $(ALL_CXXFLAGS) $< -o $@
+
+# Compile: create object files from C source files.
+.c.o:
+	$(CC) -c $(ALL_CFLAGS) $< -o $@
+
+# Compile: create assembler files from C source files.
+.c.s:
+	$(CC) -S $(ALL_CFLAGS) $< -o $@
+
+# Assemble: create object files from assembler source files.
+.S.o:
+	$(CC) -c $(ALL_ASFLAGS) $< -o $@
+
+# Automatic dependencies
+%.d: %.c
+	$(CC) -M $(ALL_CFLAGS) $< | sed "s;$(notdir $*).o:;$*.o $*.d:;" > $@
+
+%.d: %.cpp
+	$(CXX) -M $(ALL_CXXFLAGS) $< | sed "s;$(notdir $*).o:;$*.o $*.d:;" > $@
+
+# Target: clean project.
+clean:
+	$(REMOVE) output/$(PROJECT_NAME).hex output/$(PROJECT_NAME).eep output/$(PROJECT_NAME).cof output/$(PROJECT_NAME).elf \
+	output/$(PROJECT_NAME).map output/$(PROJECT_NAME).sym output/$(PROJECT_NAME).lss output/core.a \
+	$(OBJ) $(LST) $(SRC:.c=.s) $(SRC:.c=.d) $(CXXSRC:.cpp=.s) $(CXXSRC:.cpp=.d)
+
+#.PHONY:	all build elf hex eep lss sym program coff extcoff clean applet_files sizebefore sizeafter
+.PHONY:		all build elf hex eep lss sym program coff extcoff applet_files sizebefore sizeafter
+
+#include $(SRC:.c=.d)
+#include $(CXXSRC:.cpp=.d)
diff --git a/examples/pingpair_pl/pingpair_pl.pde b/examples/pingpair_pl/pingpair_pl.pde
new file mode 100644
index 0000000..96896e3
--- /dev/null
+++ b/examples/pingpair_pl/pingpair_pl.pde
@@ -0,0 +1,249 @@
+/*
+ Copyright (C) 2011 James Coliz, Jr. <maniacbug@ymail.com>
+ 
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License
+ version 2 as published by the Free Software Foundation.
+ */
+
+/**
+ * Example RF Radio Ping Pair
+ *
+ * This is an example of how to use the RF24 class.  Write this sketch to two different nodes,
+ * connect the role_pin to ground on one.  The ping node sends the current time to the pong node,
+ * which responds by sending the value back.  The ping node can then see how long the whole cycle
+ * took.
+ */
+ 
+#include <SPI.h>
+#include "nRF24L01.h"
+#include "RF24.h"
+#include "printf.h"
+
+//
+// Hardware configuration
+//
+
+// Set up nRF24L01 radio on SPI bus plus pins 8 & 9
+
+RF24 radio(8,9);
+
+// sets the role of this unit in hardware.  Connect to GND to be the 'pong' receiver
+// Leave open to be the 'ping' transmitter 
+const short role_pin = 7;
+
+const short led_pin = 13; // flash the led when a packet has been sent
+
+//
+// Topology
+//
+
+// Radio pipe addresses for the 2 nodes to communicate.
+const uint64_t pipes[2] = { 0xE8E8F0F0E1LL, 0xE8E8F0F0D2LL };
+
+//
+// Role management
+//
+// Set up role.  This sketch uses the same software for all the nodes
+// in this system.  Doing so greatly simplifies testing.  The hardware itself specifies
+// which node it is.
+//
+// This is done through the role_pin
+//
+
+// The various roles supported by this sketch
+typedef enum { role_ping_out = 1, role_pong_back } role_e;
+
+// The debug-friendly names of those roles
+const char* role_friendly_name[] = { "invalid", "Ping out", "Pong back"};
+
+// The role of the current running sketch
+role_e role;
+
+void setup(void)
+{
+  //
+  // Role
+  //
+  
+  // set up the role pin
+  pinMode(role_pin, INPUT);
+  digitalWrite(role_pin,HIGH);
+  delay(20); // Just to get a solid reading on the role pin
+  
+  // read the address pin, establish our role
+  if ( digitalRead(role_pin) )
+    role = role_ping_out;
+  else
+    role = role_pong_back;
+
+  //
+  // Print preamble
+  //
+  
+  Serial.begin(9600);
+  printf_begin();
+  printf("\n\rRF24/examples/pingpair_pl/\n\r");
+  printf("ROLE: %s\n\r",role_friendly_name[role]);
+
+  //
+  // Setup and configure rf radio
+  //
+  
+  radio.begin();
+  
+  // We will be using the Ack Payload feature, so please enable it
+  radio.enableAckPayload();
+
+  //
+  // Open pipes to other nodes for communication
+  //
+  
+  // This simple sketch opens two pipes for these two nodes to communicate
+  // back and forth.
+  // Open 'our' pipe for writing
+  // Open the 'other' pipe for reading, in position #1 (we can have up to 5 pipes open for reading)
+  
+  if ( role == role_ping_out )
+  {
+    radio.openWritingPipe(pipes[0]);
+    radio.openReadingPipe(1,pipes[1]);
+  }
+  else
+  {
+    radio.openWritingPipe(pipes[1]);
+    radio.openReadingPipe(1,pipes[0]);
+  }
+
+  //
+  // Start listening
+  //
+  
+  radio.startListening();
+
+  //
+  // Dump the configuration of the rf unit for debugging
+  //
+  
+  radio.printDetails();
+}
+
+void loop(void)
+{
+  //
+  // Ping out role.  Repeatedly send the current time
+  //
+  
+  if (role == role_ping_out)
+  {
+    // First, stop listening so we can talk.
+    radio.stopListening();
+    
+    // Take the time, and send it.  This will block until complete
+    unsigned long time = millis();
+    printf("Now sending %lu...",time);
+    radio.write( &time, sizeof(unsigned long) );
+
+    if ( radio.isAckPayloadAvailable() )
+    {
+      static char response[32];
+      radio.read(response,32);
+      printf("Ack: [%s]",response);
+
+      // try flushing the rx buffer to get the ack packet out of the system ...
+      radio.flush_rx();
+    }  
+    
+    // Now, continue listening
+    radio.startListening();
+    
+    // Wait here until we get a response, or timeout (250ms)
+    unsigned long started_waiting_at = millis();
+    bool timeout = false;
+    while ( ! radio.available() && ! timeout )
+      if (millis() - started_waiting_at > 500 )
+        timeout = true;
+    
+    // Describe the results
+    if ( timeout )
+    {
+      printf("Failed, response timed out.\n\r");
+    }
+    else
+    {
+      // Stop listening while we are clocking out the data
+      radio.stopListening();
+
+      // Dump the payloads until we've gotten everything
+      unsigned long got_time;
+      boolean done = false;
+      while (!done)
+      {
+        // Fetch the payload, and see if this was the last one.
+        done = radio.read( &got_time, sizeof(unsigned long) );
+  
+	// Spew it
+	printf("Got response %lu, round-trip delay: %lu\n\r",got_time,millis()-got_time);
+      }
+      // Begin listening again 
+      radio.startListening();
+    }
+    
+    // Try again later
+    digitalWrite(led_pin,HIGH);
+    delay(3000);
+    digitalWrite(led_pin,LOW);
+  }
+  
+  //
+  // Pong back role.  Receive each packet, dump it out, and send it back
+  //
+  
+  if ( role == role_pong_back )
+  {
+    // if there is data ready
+    if ( radio.available() )
+    {
+      // Dump the payloads until we've gotten everything
+      unsigned long got_time;
+      boolean done = false;
+      while (!done)
+      {
+        // Fetch the payload, and see if this was the last one.
+        done = radio.read( &got_time, sizeof(unsigned long) );
+  
+        // Spew it
+        printf("Got payload %lu...",got_time);
+      }
+      
+      // First, stop listening so we can talk
+      radio.stopListening();
+  
+      //delay(250);
+      
+      // necessary to flush the ack packet out
+      // but kills the entire tx queue, which I might not
+      // want in the future!!
+      radio.flush_tx();
+            
+      // Send the final one back.
+      radio.write( &got_time, sizeof(unsigned long) );  
+      printf("Sent response.\n\r");
+      
+      // Now, resume listening so we catch the next packets.
+      radio.startListening();
+     
+      //delay(250);
+
+      // Add an ack packet for the next time around
+      static unsigned id = 0;
+      static char pl_buffer[10];
+      memset(pl_buffer,' ',10);
+      pl_buffer[9] = 0;
+      snprintf(pl_buffer,10,"id %04x",id++);
+      radio.writeAckPayload( 1, pl_buffer, 10 );
+
+    }
+  }
+}
+// vim:ai:cin:sts=2 sw=2 ft=cpp
diff --git a/examples/pingpair_pl/printf.h b/examples/pingpair_pl/printf.h
new file mode 100644
index 0000000..63501e4
--- /dev/null
+++ b/examples/pingpair_pl/printf.h
@@ -0,0 +1,33 @@
+/*
+ Copyright (C) 2011 James Coliz, Jr. <maniacbug@ymail.com>
+ 
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License
+ version 2 as published by the Free Software Foundation.
+ */
+ 
+/**
+ * @file printf.h
+ *
+ * Setup necessary to direct stdout to the Arduino Serial library, which
+ * enables 'printf'
+ */
+
+#ifndef __PRINTF_H__
+#define __PRINTF_H__
+
+#include "WProgram.h"
+
+int serial_putc( char c, FILE *t ) 
+{
+  Serial.write( c );
+
+  return c;
+} 
+
+void printf_begin(void)
+{
+  fdevopen( &serial_putc, 0 );
+}
+
+#endif // __PRINTF_H__
diff --git a/nRF24L01.h b/nRF24L01.h
index 10aedb3..5f4d1b8 100644
--- a/nRF24L01.h
+++ b/nRF24L01.h
@@ -47,6 +47,8 @@
 #define RX_PW_P4    0x15
 #define RX_PW_P5    0x16
 #define FIFO_STATUS 0x17
+#define DYNPD	    0x1C
+#define FEATURE	    0x1D
 
 /* Bit Mnemonics */
 #define MASK_RX_DR  6
@@ -87,13 +89,25 @@
 #define TX_EMPTY    4
 #define RX_FULL     1
 #define RX_EMPTY    0
+#define DPL_P5	    5
+#define DPL_P4	    4
+#define DPL_P3	    3
+#define DPL_P2	    2
+#define DPL_P1	    1
+#define DPL_P0	    0
+#define EN_DPL	    2
+#define EN_ACK_PAY  1
+#define EN_DYN_ACK  0
 
 /* Instruction Mnemonics */
 #define R_REGISTER    0x00
 #define W_REGISTER    0x20
 #define REGISTER_MASK 0x1F
+#define ACTIVATE      0x50
+#define R_RX_PL_WID   0x60
 #define R_RX_PAYLOAD  0x61
 #define W_TX_PAYLOAD  0xA0
+#define W_ACK_PAYLOAD 0xA8
 #define FLUSH_TX      0xE1
 #define FLUSH_RX      0xE2
 #define REUSE_TX_PL   0xE3