diff --git a/tnc/codec2.py b/tnc/codec2.py
index 38e2d1fc..237080e3 100644
--- a/tnc/codec2.py
+++ b/tnc/codec2.py
@@ -16,11 +16,17 @@ class FREEDV_MODE(Enum):
     datac0 = 14
     datac1 = 10
     datac3 = 12
-    
-def freedv_get_mode(mode):
+    allmodes = 255
+
+# function for returning the mode value
+def freedv_get_mode_value_by_name(mode):
     return FREEDV_MODE[mode].value
 
-
+# function for returning the mode name
+def freedv_get_mode_name_by_value(mode):
+    return FREEDV_MODE(mode).name
+    
+    
 # check if we are running in a pyinstaller environment
 try:
     app_path = sys._MEIPASS
diff --git a/tnc/data_handler.py b/tnc/data_handler.py
index cbe1f68e..96df8f8f 100644
--- a/tnc/data_handler.py
+++ b/tnc/data_handler.py
@@ -714,7 +714,7 @@ class DATA():
         connection_frame[1:2]   = static.DXCALLSIGN_CRC8
         connection_frame[2:3]   = static.MYCALLSIGN_CRC8
         connection_frame[3:9]   = static.MYCALLSIGN
-        connection_frame[9:10]   = bytes([0]) # ONE BYTE LEFT FOR OTHER THINGS
+        connection_frame[9:10]   = bytes([mode])
         connection_frame[10:12]  = data_len.to_bytes(2, byteorder='big')
         connection_frame[12:13] = bytes([compression_factor])
         connection_frame[13:14] = bytes([n_frames_per_burst])    
@@ -761,6 +761,20 @@ class DATA():
         static.TOTAL_BYTES = int.from_bytes(bytes(data_in[10:12]), "big") # kBytes
         static.ARQ_COMPRESSION_FACTOR = float(int.from_bytes(bytes(data_in[12:13]), "big") / 10)
         n_frames_per_burst = int.from_bytes(bytes(data_in[13:14]), "big")    
+        mode = int.from_bytes(bytes(data_in[9:10]), "big") 
+
+        # set modes we want to listening to
+        mode_name = codec2.freedv_get_mode_name_by_value(mode)
+        if mode_name == 'datac1':
+            modem.RECEIVE_DATAC1 = True
+        elif mode_name == 'datac3':
+            modem.RECEIVE_DATAC3 = True
+        elif mode_name == 'allmodes':
+            modem.RECEIVE_DATAC1 = True
+            modem.RECEIVE_DATAC3 = True
+
+
+
         
         #we need to find a way how to do this. this isn't working anymore since we mode to a class based module
         #modem.set_frames_per_burst(n_frames_per_burst)
@@ -1027,6 +1041,10 @@ class DATA():
         static.RX_FRAME_BUFFER = b'' 
         self.burst_ack_snr= 255
 
+        # reset modem receiving state to reduce cpu load
+        modem.RECEIVE_DATAC1 = False
+        modem.RECEIVE_DATAC3 = False
+            
     def arq_reset_ack(self,state:bool):
 
         self.burst_ack = state
diff --git a/tnc/modem.py b/tnc/modem.py
index 87710238..33e168c0 100644
--- a/tnc/modem.py
+++ b/tnc/modem.py
@@ -88,6 +88,10 @@ MODEM_RECEIVED_QUEUE = queue.Queue()
 MODEM_TRANSMIT_QUEUE = queue.Queue()
 static.TRANSMITTING = False
 
+# receive only specific modes to reduce cpu load
+RECEIVE_DATAC1 = False
+RECEIVE_DATAC3 = False
+
 class RF():
 
     def __init__(self):
@@ -217,14 +221,15 @@ class RF():
         x = np.frombuffer(data_in48k, dtype=np.int16)
         x = self.resampler.resample48_to_8(x)    
 
-        # avoid buffer overflow
+        
+        # avoid buffer overflow by filling only if buffer not full
         if not self.datac0_buffer.nbuffer+len(x) > self.datac0_buffer.size:
             self.datac0_buffer.push(x)
-        # avoid buffer overflow    
-        if not self.datac1_buffer.nbuffer+len(x) > self.datac1_buffer.size:
+        # avoid buffer overflow by filling only if buffer not full and selected datachannel mode
+        if not self.datac1_buffer.nbuffer+len(x) > self.datac1_buffer.size and RECEIVE_DATAC1:
             self.datac1_buffer.push(x)
-        # avoid buffer overflow
-        if not self.datac3_buffer.nbuffer+len(x) > self.datac3_buffer.size:
+        # avoid buffer overflow by filling only if buffer not full and selected datachannel mode
+        if not self.datac3_buffer.nbuffer+len(x) > self.datac3_buffer.size and RECEIVE_DATAC3:
             self.datac3_buffer.push(x)
         
         
@@ -245,7 +250,6 @@ class RF():
         # toggle ptt early to save some time
         static.PTT_STATE = self.hamlib.set_ptt(True)
         # open codec2 instance       
-        #self.MODE = codec2.freedv_get_mode_value_by_name(mode)
         self.MODE = mode
         freedv = cast(codec2.api.freedv_open(self.MODE), c_void_p)
 
@@ -340,12 +344,10 @@ class RF():
         threading.Event().set()
 
     def audio_datac0(self):             
-        nbytes_datac0 = 0
-        
+        nbytes_datac0 = 0    
         while self.audio_stream.is_active():
             threading.Event().wait(0.01)
             while self.datac0_buffer.nbuffer >= self.datac0_nin:        
-
                 # demodulate audio
                 nbytes_datac0 = codec2.api.freedv_rawdatarx(self.datac0_freedv, self.datac0_bytes_out, self.datac0_buffer.buffer.ctypes)
                 self.datac0_buffer.pop(self.datac0_nin)
@@ -360,7 +362,6 @@ class RF():
         while self.audio_stream.is_active():
             threading.Event().wait(0.01)
             while self.datac1_buffer.nbuffer >= self.datac1_nin:
-
                     # demodulate audio
                     nbytes_datac1 = codec2.api.freedv_rawdatarx(self.datac1_freedv, self.datac1_bytes_out, self.datac1_buffer.buffer.ctypes)
                     self.datac1_buffer.pop(self.datac1_nin)
@@ -375,7 +376,6 @@ class RF():
         while self.audio_stream.is_active():
             threading.Event().wait(0.01)
             while self.datac3_buffer.nbuffer >= self.datac3_nin:
-
                 # demodulate audio    
                 nbytes_datac3 = codec2.api.freedv_rawdatarx(self.datac3_freedv, self.datac3_bytes_out, self.datac3_buffer.buffer.ctypes)
                 self.datac3_buffer.pop(self.datac3_nin)