diff --git a/.gitignore b/.gitignore
index cc1f0be..14ffd8a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@
 /SP5WWP/m17-packet/m17-packet-encode
 /SP5WWP/m17-packet/m17-packet-decode
 /SP5WWP/.vscode
+*.json
diff --git a/SP5WWP/lib/Makefile b/SP5WWP/lib/Makefile
index 3617bdd..396e9d0 100644
--- a/SP5WWP/lib/Makefile
+++ b/SP5WWP/lib/Makefile
@@ -15,6 +15,9 @@ clean:
 fclean:
 	rm -f $(TARGET)
 
+install:
+	sudo install $(TARGET) /usr/local/lib
+
 $(TARGET): $(OBJS)
 	$(CC) $(CFLAGS) $(OBJS) -o $@ $(LDFLAGS)
 
diff --git a/SP5WWP/lib/encode/symbols.c b/SP5WWP/lib/encode/symbols.c
index f80c897..614574f 100644
--- a/SP5WWP/lib/encode/symbols.c
+++ b/SP5WWP/lib/encode/symbols.c
@@ -2,9 +2,12 @@
 // M17 C library - encode/symbols.c
 //
 // Wojciech Kaczmarski, SP5WWP
-// M17 Project, 29 December 2023
+// M17 Project, 5 January 2024
 //--------------------------------------------------------------------
 #include "symbols.h"
 
-// dibits-symbols map (TX)
+//dibits-symbols map (TX)
 const int8_t symbol_map[4]={+1, +3, -1, -3};
+
+//End of Transmission symbol pattern
+const float eot_symbols[8]={+3, +3, +3, +3, +3, +3, -3, +3};
diff --git a/SP5WWP/lib/encode/symbols.h b/SP5WWP/lib/encode/symbols.h
index 9016d69..0ebdaa6 100644
--- a/SP5WWP/lib/encode/symbols.h
+++ b/SP5WWP/lib/encode/symbols.h
@@ -2,7 +2,7 @@
 // M17 C library - encode/symbols.h
 //
 // Wojciech Kaczmarski, SP5WWP
-// M17 Project, 28 December 2023
+// M17 Project, 5 January 2024
 //-------------------------------
 #pragma once
 
@@ -11,9 +11,12 @@ extern "C" {
 #endif
 #include <stdint.h>
 
-// dibits-symbols map (TX)
+//dibits-symbols map (TX)
 extern const int8_t symbol_map[4];
 
+//End of Transmission symbol pattern
+extern const float eot_symbols[8];
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/SP5WWP/lib/lib.c b/SP5WWP/lib/lib.c
index 92a5694..f886783 100644
--- a/SP5WWP/lib/lib.c
+++ b/SP5WWP/lib/lib.c
@@ -2,66 +2,80 @@
 // M17 C library - lib.c
 //
 // Wojciech Kaczmarski, SP5WWP
-// M17 Project, 29 December 2023
+// M17 Project, 5 January 2024
 //--------------------------------------------------------------------
-#include <stdio.h>
 #include <encode/symbols.h>
 #include "lib.h"
 
-//misc
-void send_preamble(const uint8_t type)
+/**
+ * @brief Generate symbol stream for a preamble.
+ * 
+ * @param out Frame buffer (192 floats)
+ * @param cnt Pointer to a variable holding the number of written symbols.
+ * @param type Preamble type (pre-BERT or pre-LSF).
+ */
+void send_preamble(float out[SYM_PER_FRA], uint32_t *cnt, const uint8_t type)
 {
-    float symb;
-
     if(type) //pre-BERT
     {
-        for(uint16_t i=0; i<192/2; i++) //40ms * 4800 = 192
+        for(uint16_t i=0; i<SYM_PER_FRA/2; i++) //40ms * 4800 = 192
         {
-            symb=-3.0;
-            fwrite((uint8_t*)&symb, sizeof(float), 1, stdout);
-            symb=+3.0;
-            fwrite((uint8_t*)&symb, sizeof(float), 1, stdout);
+            out[(*cnt)++]=-3.0;
+            out[(*cnt)++]=+3.0;
         }
     }
     else //pre-LSF
     {
-        for(uint16_t i=0; i<192/2; i++) //40ms * 4800 = 192
+        for(uint16_t i=0; i<SYM_PER_FRA/2; i++) //40ms * 4800 = 192
         {
-            symb=+3.0;
-            fwrite((uint8_t*)&symb, sizeof(float), 1, stdout);
-            symb=-3.0;
-            fwrite((uint8_t*)&symb, sizeof(float), 1, stdout);
+            out[(*cnt)++]=+3.0;
+            out[(*cnt)++]=-3.0;
         }
     }
 }
 
-void send_syncword(const uint16_t syncword)
+/**
+ * @brief Generate symbol stream for a syncword.
+ * 
+ * @param out Output buffer (8 floats).
+ * @param cnt Pointer to a variable holding the number of written symbols.
+ * @param syncword Syncword.
+ */
+void send_syncword(float out[SYM_PER_SWD], uint32_t *cnt, const uint16_t syncword)
 {
-    float symb;
-
-    for(uint8_t i=0; i<16; i+=2)
+    for(uint8_t i=0; i<SYM_PER_SWD*2; i+=2)
     {
-        symb=symbol_map[(syncword>>(14-i))&3];
-        fwrite((uint8_t*)&symb, sizeof(float), 1, stdout);
+        out[(*cnt)++]=symbol_map[(syncword>>(14-i))&3];
     }
 }
 
 //send the data (can be used for both LSF and frames)
-void send_data(const uint8_t* in)
+/**
+ * @brief Generate symbol stream for frame contents (without syncword).
+ * Can be used for both LSF and data frames.
+ * 
+ * @param out Output buffer (184 floats).
+ * @param cnt Pointer to a variable holding the number of written symbols.
+ * @param in Data input.
+ */
+void send_data(float out[SYM_PER_PLD], uint32_t *cnt, const uint8_t* in)
 {
-	float s=0.0;
 	for(uint16_t i=0; i<SYM_PER_PLD; i++) //40ms * 4800 - 8 (syncword)
 	{
-		s=symbol_map[in[2*i]*2+in[2*i+1]];
-		fwrite((uint8_t*)&s, sizeof(float), 1, stdout);
+        out[(*cnt)++]=symbol_map[in[2*i]*2+in[2*i+1]];
 	}
 }
 
-void send_eot(void)
+/**
+ * @brief Generate symbol stream for the End of Transmission marker.
+ * 
+ * @param out Output buffer (192 floats).
+ * @param cnt Pointer to a variable holding the number of written symbols.
+ */
+void send_eot(float out[SYM_PER_FRA], uint32_t *cnt)
 {
-    float symb=+3.0;
-    for(uint16_t i=0; i<192; i++) //40ms * 4800 = 192
+    for(uint16_t i=0; i<SYM_PER_FRA; i++) //40ms * 4800 = 192
     {
-        fwrite((uint8_t*)&symb, sizeof(float), 1, stdout);
+        out[(*cnt)++]=eot_symbols[i%8];
     }
 }
diff --git a/SP5WWP/lib/lib.h b/SP5WWP/lib/lib.h
index 0cf72d0..bb1089f 100644
--- a/SP5WWP/lib/lib.h
+++ b/SP5WWP/lib/lib.h
@@ -2,7 +2,7 @@
 // M17 C library - lib.h
 //
 // Wojciech Kaczmarski, SP5WWP
-// M17 Project, 28 December 2023
+// M17 Project, 5 January 2024
 //-------------------------------
 #pragma once
 
@@ -22,10 +22,10 @@ extern "C" {
 //L2 metric threshold
 #define DIST_THRESH         2.0f                    //threshold for distance (syncword detection)
 
-void send_preamble(const uint8_t type);
-void send_syncword(const uint16_t syncword);
-void send_data(const uint8_t* in);
-void send_eot(void);
+void send_preamble(float out[SYM_PER_FRA], uint32_t *cnt, const uint8_t type);
+void send_syncword(float out[SYM_PER_SWD], uint32_t *cnt, const uint16_t syncword);
+void send_data(float out[SYM_PER_PLD], uint32_t *cnt, const uint8_t* in);
+void send_eot(float out[SYM_PER_FRA], uint32_t *cnt);
 
 #ifdef __cplusplus
 }
diff --git a/SP5WWP/m17-coder/m17-coder-sym.c b/SP5WWP/m17-coder/m17-coder-sym.c
index 02db80c..bd710da 100644
--- a/SP5WWP/m17-coder/m17-coder-sym.c
+++ b/SP5WWP/m17-coder/m17-coder-sym.c
@@ -22,6 +22,9 @@ uint8_t lich_encoded[12];           //96 bits packed, encoded LICH
 uint8_t enc_bits[SYM_PER_PLD*2];    //type-2 bits, unpacked
 uint8_t rf_bits[SYM_PER_PLD*2];     //type-4 bits, unpacked
 
+float frame_buff[192];
+uint32_t frame_buff_cnt;
+
 uint8_t data[16], next_data[16];    //raw payload, packed bits
 uint16_t fn=0;                      //16-bit Frame Number (for the stream mode)
 uint8_t lich_cnt=0;                 //0..5 LICH counter
@@ -66,7 +69,8 @@ int main(void)
         if(got_lsf) //stream frames
         {
             //send stream frame syncword
-            send_syncword(SYNC_STR);
+            frame_buff_cnt=0;
+            send_syncword(frame_buff, &frame_buff_cnt, SYNC_STR);
 
             //extract LICH from the whole LSF
             switch(lich_cnt)
@@ -178,7 +182,9 @@ int main(void)
                 fwrite((uint8_t*)&s, sizeof(float), 1, stdout);*/
 
 			//send frame data
-			send_data(rf_bits);
+            frame_buff_cnt=0;
+			send_data(frame_buff, &frame_buff_cnt, rf_bits);
+            fwrite((uint8_t*)frame_buff, SYM_PER_FRA*sizeof(float), 1, stdout);
 
             /*printf("\tDATA: ");
             for(uint8_t i=0; i<16; i++)
@@ -204,11 +210,15 @@ int main(void)
             //encode LSF data
             conv_encode_LSF(enc_bits, &lsf);
 
-            //send out the preamble and LSF
-			send_preamble(0); //0 - LSF preamble, as opposed to 1 - BERT preamble
+            //send out the preamble
+            frame_buff_cnt=0;
+			send_preamble(frame_buff, &frame_buff_cnt, 0); //0 - LSF preamble, as opposed to 1 - BERT preamble
+            fwrite((uint8_t*)frame_buff, SYM_PER_FRA*sizeof(float), 1, stdout);
 
             //send LSF syncword
-			send_syncword(SYNC_LSF);
+            frame_buff_cnt=0;
+			send_syncword(frame_buff, &frame_buff_cnt, SYNC_LSF);
+            fwrite((uint8_t*)frame_buff, SYM_PER_SWD*sizeof(float), 1, stdout);
 
             //reorder bits
             for(uint16_t i=0; i<SYM_PER_PLD*2; i++)
@@ -227,7 +237,9 @@ int main(void)
             }
 
 			//send LSF data
-			send_data(rf_bits);
+            frame_buff_cnt=0;
+			send_data(frame_buff, &frame_buff_cnt, rf_bits);
+            fwrite((uint8_t*)frame_buff, SYM_PER_PLD*sizeof(float), 1, stdout);
 
             //send dummy symbols (debug)
             /*float s=0.0;
@@ -253,7 +265,11 @@ int main(void)
 		}
 
         if(finished)
-            send_eot();
+        {
+            frame_buff_cnt=0;
+            send_eot(frame_buff, &frame_buff_cnt);
+            fwrite((uint8_t*)frame_buff, SYM_PER_PLD*sizeof(float), 1, stdout);
+        }
 	}
 
 	return 0;