diff --git a/master/master/config.h b/master/master/config.h
--- a/master/master/config.h
+++ b/master/master/config.h
@@ -12,4 +12,16 @@
 #define F_CPU 11059200
 #define MODULE_ID '1'
 
+// --------------------------------------------------------------------------
+// AX.25 config (ax25.c)
+// --------------------------------------------------------------------------
+
+// TX delay in milliseconds
+#define TX_DELAY      300
+
+// Maximum packet delay
+#define MAX_PACKET_LEN 512  // bytes
+
+
+
 #endif /* CONFIG_H_ */
\ No newline at end of file
diff --git a/master/master/lib/afsk.c b/master/master/lib/afsk.c
--- a/master/master/lib/afsk.c
+++ b/master/master/lib/afsk.c
@@ -5,7 +5,8 @@
  *  Author: ethanzonca
  */
 
-#define F_CPU 11059200
+
+#include "../config.h"
 
 #include <stdint.h>
 #include <stdbool.h>
diff --git a/master/master/lib/afsk.h b/master/master/lib/afsk.h
--- a/master/master/lib/afsk.h
+++ b/master/master/lib/afsk.h
@@ -9,6 +9,11 @@
 #ifndef AFSK_H_
 #define AFSK_H_
 
+// Private
+void afsk_output_sample(uint8_t s);
+void afsk_timer_stop();
+
+// Public
 void afsk_setup();
 void afsk_test();
 void afsk_send(const uint8_t *buffer, int len);
diff --git a/master/master/lib/ax25.c b/master/master/lib/ax25.c
--- a/master/master/lib/ax25.c
+++ b/master/master/lib/ax25.c
@@ -5,13 +5,12 @@
  *  Author: ethanzonca
  */ 
 
-/*
+
 #include <inttypes.h>
+#include "../config.h"
+#include "ax25.h"
 #include "afsk.h"
 
-// Module constants
-#define MAX_PACKET_LEN 512  // bytes
-
 // Module globals
 static uint16_t crc;
 static uint8_t ones_in_a_row;
@@ -134,4 +133,3 @@ void ax25_flush_frame()
 	afsk_send(packet, packet_size);
 	afsk_start();
 }
-*/
\ No newline at end of file
diff --git a/master/master/lib/ax25.h b/master/master/lib/ax25.h
--- a/master/master/lib/ax25.h
+++ b/master/master/lib/ax25.h
@@ -9,6 +9,11 @@
 #ifndef AX25_H_
 #define AX25_H_
 
+struct s_address {
+	char callsign[7];
+	unsigned char ssid;
+};
+
 void ax25_send_byte(uint8_t a_byte);
 void ax25_send_flag();
 void ax25_send_string(const char *string);