diff --git a/CMakeLists.txt b/CMakeLists.txt
index 285fa40d..9abc5b18 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,14 +17,35 @@ else()
     find_package(codec2 REQUIRED)
 endif()
 
+# test variables
+set(FRAMESPERBURST 3)
+set(BURSTS 1)
+set(TESTFRAMES 3)
+
 add_test(NAME 000_audio_tests
          COMMAND sh -c "cd ${CMAKE_CURRENT_SOURCE_DIR}/test/000_audio_tests;
                             python3 sinustest.py")
-add_test(NAME 001_highsnr_stdio
+
+add_test(NAME 001_highsnr_stdio_P<>C
          COMMAND sh -c "export LD_LIBRARY_PATH=${CODEC2_BUILD_DIR}/src;
                         PATH=$PATH:${CODEC2_BUILD_DIR}/src;
                         cd ${CMAKE_CURRENT_SOURCE_DIR}/test/001_highsnr_stdio_audio;
-                        python3 test_tx.py --mode 14 --delay 500 --framesperburst 3 --bursts 1 |
-                        freedv_data_raw_rx datac0 - - --framesperburst 3 | hexdump -C")
-        set_tests_properties(001_highsnr_stdio PROPERTIES PASS_REGULAR_EXPRESSION "HELLO WORLD")
+                        python3 test_tx.py --mode 14 --delay 500 --framesperburst ${FRAMESPERBURST} --bursts ${BURSTS} |
+                        freedv_data_raw_rx datac0 - - --framesperburst ${FRAMESPERBURST} | hexdump -C")
+        set_tests_properties(001_highsnr_stdio_P<>C PROPERTIES PASS_REGULAR_EXPRESSION "HELLO WORLD")
 
+add_test(NAME 001_highsnr_stdio_C<>P
+         COMMAND sh -c "export LD_LIBRARY_PATH=${CODEC2_BUILD_DIR}/src;
+                        PATH=$PATH:${CODEC2_BUILD_DIR}/src;
+                        cd ${CMAKE_CURRENT_SOURCE_DIR}/test/001_highsnr_stdio_audio;
+                        freedv_data_raw_tx --testframes ${TESTFRAMES} --bursts ${BURSTS} --framesperburst ${FRAMESPERBURST} datac0 /dev/zero - |
+                        python3 test_rx.py --mode 14 --framesperburst ${FRAMESPERBURST} --bursts ${BURSTS}")
+        set_tests_properties(001_highsnr_stdio_C<>P PROPERTIES PASS_REGULAR_EXPRESSION "RECEIVED BURSTS: ${BURSTS} RECEIVED FRAMES: ${FRAMESPERBURST}")
+
+add_test(NAME 001_highsnr_stdio_P<>P
+         COMMAND sh -c "export LD_LIBRARY_PATH=${CODEC2_BUILD_DIR}/src;
+                        PATH=$PATH:${CODEC2_BUILD_DIR}/src;
+                        cd ${CMAKE_CURRENT_SOURCE_DIR}/test/001_highsnr_stdio_audio;
+                        python3 test_tx.py --mode 14 --delay 500 --framesperburst ${FRAMESPERBURST} --bursts ${BURSTS} |
+                        python3 test_rx.py --mode 14 --framesperburst ${FRAMESPERBURST} --bursts ${BURSTS}")
+        set_tests_properties(001_highsnr_stdio_P<>P PROPERTIES PASS_REGULAR_EXPRESSION "RECEIVED BURSTS: ${BURSTS} RECEIVED FRAMES: ${FRAMESPERBURST}")
diff --git a/test/001_highsnr_stdio_audio/test_rx.py b/test/001_highsnr_stdio_audio/test_rx.py
index 298f11ce..a854dbc5 100644
--- a/test/001_highsnr_stdio_audio/test_rx.py
+++ b/test/001_highsnr_stdio_audio/test_rx.py
@@ -21,9 +21,8 @@ import argparse
 #--------------------------------------------GET PARAMETER INPUTS  
 parser = argparse.ArgumentParser(description='Simons TEST TNC')
 parser.add_argument('--bursts', dest="N_BURSTS", default=0, type=int)
-parser.add_argument('--frames', dest="N_FRAMES_PER_BURST", default=0, type=int)
-parser.add_argument('--mode', dest="FREEDV_MODE", default=0, type=int)
-parser.add_argument('--input', dest="DATA_INPUT", type=str)  
+parser.add_argument('--framesperburst', dest="N_FRAMES_PER_BURST", default=0, type=int)
+parser.add_argument('--mode', dest="FREEDV_MODE", default=14, type=int)
 parser.add_argument('--audioinput', dest="AUDIO_INPUT", default=0, type=int)  
 parser.add_argument('--debug', dest="DEBUGGING_MODE", action="store_true")  
 
@@ -31,39 +30,19 @@ args = parser.parse_args()
 
 N_BURSTS = args.N_BURSTS
 N_FRAMES_PER_BURST = args.N_FRAMES_PER_BURST
-DATA_INPUT = args.DATA_INPUT
 AUDIO_INPUT_DEVICE = args.AUDIO_INPUT
-FREEDV_MODE = args.FREEDV_MODE
+MODE = args.FREEDV_MODE
 DEBUGGING_MODE = args.DEBUGGING_MODE
 
-# 1024 good for mode 6
+
+# AUDIO PARAMETERS
 AUDIO_FRAMES_PER_BUFFER = 2048 
 MODEM_SAMPLE_RATE = 8000
+AUDIO_SAMPLE_RATE_TX = 48000
 
-
-
-
-
-
-
-
-              
-        #-------------------------------------------- LOAD FREEDV
-             
-libname = "libcodec2.so"
-c_lib = ctypes.CDLL(libname)
-
-        #--------------------------------------------CREATE PYAUDIO  INSTANCE
-        
-        
-        #--------------------------------------------GET SUPPORTED SAMPLE RATES FROM SOUND DEVICE
-        
-        
-        #--------------------------------------------OPEN AUDIO CHANNEL RX
-        
-if DATA_INPUT == "audio":
+# check if we want to use an audio device then do an pyaudio init
+if AUDIO_INPUT_DEVICE != 0: 
     p = pyaudio.PyAudio()
-    AUDIO_SAMPLE_RATE_RX = int(p.get_device_info_by_index(AUDIO_INPUT_DEVICE)['defaultSampleRate'])
     stream_rx = p.open(format=pyaudio.paInt16, 
                             channels=1,
                             rate=AUDIO_SAMPLE_RATE_RX,
@@ -72,18 +51,48 @@ if DATA_INPUT == "audio":
                             input_device_index=AUDIO_INPUT_DEVICE,
                             ) 
 
+# LOAD FREEDV
+libname = "libcodec2.so"
+c_lib = ctypes.CDLL(libname)
 
-    # GENERAL PARAMETERS        
-c_lib.freedv_open.restype = ctypes.POINTER(ctypes.c_ubyte)
-                
+# ctypes function init        
+
+c_lib.freedv_open.argype = [c_int]
+c_lib.freedv_open.restype = c_void_p
+
+c_lib.freedv_get_bits_per_modem_frame.argtype = [c_void_p]
+c_lib.freedv_get_bits_per_modem_frame.restype = c_int
+
+c_lib.freedv_nin.argtype = [c_void_p]
+c_lib.freedv_nin.restype = c_int
+
+c_lib.freedv_rawdatarx.argtype = [c_void_p, c_char_p, c_char_p]
+c_lib.freedv_rawdatarx.restype = c_int
+
+c_lib.freedv_get_n_max_modem_samples.argtype = [c_void_p]
+c_lib.freedv_get_n_max_modem_samples.restype = c_int
+
+c_lib.freedv_set_frames_per_burst.argtype = [c_void_p, c_int]
+c_lib.freedv_set_frames_per_burst.restype = c_void_p
+      
+c_lib.freedv_get_rx_status.argtype = [c_void_p]
+c_lib.freedv_get_rx_status.restype = c_int      
+
+      
+# ----------------------------------------------------------------
+              
 
      # DATA CHANNEL INITIALISATION
 
-freedv = c_lib.freedv_open(FREEDV_MODE)
+# open codec2 instance        
+freedv = cast(c_lib.freedv_open(MODE), c_void_p)
+
+# get number of bytes per frame for mode
 bytes_per_frame = int(c_lib.freedv_get_bits_per_modem_frame(freedv)/8)
+payload_bytes_per_frame = bytes_per_frame -2
+
 n_max_modem_samples = c_lib.freedv_get_n_max_modem_samples(freedv)     
-bytes_out = (ctypes.c_ubyte * bytes_per_frame) #bytes_per_frame
-bytes_out = bytes_out() #get pointer from bytes_out
+bytes_out = create_string_buffer(bytes_per_frame * 2)
 
 c_lib.freedv_set_frames_per_burst(freedv,N_FRAMES_PER_BURST)
 
@@ -92,32 +101,32 @@ total_n_bytes = 0
 rx_total_frames = 0
 rx_frames = 0
 rx_bursts = 0
+timeout = time.time() + 10
 receive = True
-while receive == True:
-    time.sleep(0.01)
+
+while receive and time.time() < timeout:
 
     data_in = b''
-    if DATA_INPUT == "audio":
+    if AUDIO_INPUT_DEVICE != 0: 
         
         nin = c_lib.freedv_nin(freedv)
         nin_converted = int(nin*(AUDIO_SAMPLE_RATE_RX/MODEM_SAMPLE_RATE))
         if DEBUGGING_MODE == True:
-            print("-----------------------------")
-            print("NIN:  " + str(nin) + " [ " + str(nin_converted) + " ]")
+            print(f"NIN:  {nin} [{nin_converted}]", file=sys.stderr)
         
         data_in = stream_rx.read(nin_converted,  exception_on_overflow = False)  
         data_in = audioop.ratecv(data_in,2,1,AUDIO_SAMPLE_RATE_RX, MODEM_SAMPLE_RATE, None) 
         data_in = data_in[0].rstrip(b'\x00') 
 
     else:
-        nin = c_lib.freedv_nin(freedv)*2
+        nin = c_lib.freedv_nin(freedv) * 2
         data_in = sys.stdin.buffer.read(nin)
 
-    c_lib.freedv_rawdatarx.argtype = [ctypes.POINTER(ctypes.c_ubyte), bytes_out, data_in] # check if really neccessary 
     nbytes = c_lib.freedv_rawdatarx(freedv, bytes_out, data_in) # demodulate audio
     total_n_bytes = total_n_bytes + nbytes
+    
     if DEBUGGING_MODE == True:
-        print("SYNC: " + str(c_lib.freedv_get_rx_status(freedv)))
+        print(f"SYNC: {c_lib.freedv_get_rx_status(freedv)}", file=sys.stderr)
         
     if nbytes == bytes_per_frame:
         rx_total_frames = rx_total_frames + 1
@@ -126,13 +135,15 @@ while receive == True:
         if rx_frames == N_FRAMES_PER_BURST:
             rx_frames = 0
             rx_bursts = rx_bursts + 1
-            #c_lib.freedv_set_sync(freedv,0) #this should be automatically done by c_lib.freedv_set_frames_per_burst(freedv,N_FRAMES_PER_BURST)
+            
         
     if rx_bursts == N_BURSTS:
         receive = False   
                    
-print("------------------------------")
-print("BURSTS: " + str(rx_bursts))
-print("TOTAL RECEIVED BYTES: " + str(total_n_bytes)) 
-print("RECEIVED FRAMES: " + str(rx_total_frames)) 
 
+print(f"RECEIVED BURSTS: {rx_bursts} RECEIVED FRAMES: {rx_total_frames}", file=sys.stderr)
+
+# and at last check if we had an openend pyaudio instance and close it
+if AUDIO_INPUT_DEVICE != 0: 
+    stream_tx.close()
+    p.terminate()
diff --git a/test/001_highsnr_stdio_audio/test_tx.py b/test/001_highsnr_stdio_audio/test_tx.py
index 30794dd8..9efe7c26 100644
--- a/test/001_highsnr_stdio_audio/test_tx.py
+++ b/test/001_highsnr_stdio_audio/test_tx.py
@@ -17,8 +17,7 @@ parser = argparse.ArgumentParser(description='Simons TEST TNC')
 parser.add_argument('--bursts', dest="N_BURSTS", default=0, type=int)
 parser.add_argument('--framesperburst', dest="N_FRAMES_PER_BURST", default=0, type=int)
 parser.add_argument('--delay', dest="DELAY_BETWEEN_BURSTS", default=0, type=int)
-parser.add_argument('--mode', dest="FREEDV_MODE", default=0, type=int)
-parser.add_argument('--output', dest="DATA_OUTPUT", type=str)  
+parser.add_argument('--mode', dest="FREEDV_MODE", default=14, type=int)
 parser.add_argument('--audiooutput', dest="AUDIO_OUTPUT", default=0, type=int) 
 
 args = parser.parse_args()
@@ -26,17 +25,17 @@ args = parser.parse_args()
 N_BURSTS = args.N_BURSTS
 N_FRAMES_PER_BURST = args.N_FRAMES_PER_BURST
 DELAY_BETWEEN_BURSTS = args.DELAY_BETWEEN_BURSTS/1000
-DATA_OUTPUT = args.DATA_OUTPUT
 AUDIO_OUTPUT_DEVICE = args.AUDIO_OUTPUT
 MODE = args.FREEDV_MODE
 
+
 # AUDIO PARAMETERS
 AUDIO_FRAMES_PER_BUFFER = 2048 
 MODEM_SAMPLE_RATE = 8000
 AUDIO_SAMPLE_RATE_TX = 48000
 
 # check if we want to use an audio device then do an pyaudio init
-if DATA_OUTPUT == "audio": 
+if AUDIO_OUTPUT_DEVICE != 0: 
     # pyaudio init
     p = pyaudio.PyAudio()
     stream_tx = p.open(format=pyaudio.paInt16,
@@ -143,7 +142,7 @@ for i in range(1,N_BURSTS+1):
     print(f"samples_delay: {samples_delay} DELAY_BETWEEN_BURSTS: {DELAY_BETWEEN_BURSTS}", file=sys.stderr)
     
     # check if we want to use an audio device or stdout
-    if DATA_OUTPUT == "audio":  
+    if AUDIO_OUTPUT_DEVICE != 0: 
         
         # sample rate conversion from 8000Hz to 48000Hz
         audio = audioop.ratecv(txbuffer,2,1,MODEM_SAMPLE_RATE, AUDIO_SAMPLE_RATE_TX, None)                                           
@@ -156,6 +155,6 @@ for i in range(1,N_BURSTS+1):
 
 
 # and at last check if we had an openend pyaudio instance and close it
-if DATA_OUTPUT == "audio":          
+if AUDIO_OUTPUT_DEVICE != 0: 
     stream_tx.close()
     p.terminate()