diff --git a/project/Core/Inc/modbus-tcp.h b/project/Core/Inc/modbus_tcp.h
similarity index 100%
rename from project/Core/Inc/modbus-tcp.h
rename to project/Core/Inc/modbus_tcp.h
diff --git a/project/Core/Src/main.c b/project/Core/Src/main.c
index b0db874..56d1184 100644
--- a/project/Core/Src/main.c
+++ b/project/Core/Src/main.c
@@ -29,6 +29,7 @@
 #include "llfs.h"
 #include "lcd_api.h"
 #include "tftp.h"
+#include "modbus_tcp.h"
 
 /* USER CODE END Includes */
 
diff --git a/project/Core/Src/modbus-tcp.c b/project/Core/Src/modbus_tcp.c
similarity index 98%
rename from project/Core/Src/modbus-tcp.c
rename to project/Core/Src/modbus_tcp.c
index ada71af..f657571 100644
--- a/project/Core/Src/modbus-tcp.c
+++ b/project/Core/Src/modbus_tcp.c
@@ -1,6 +1,8 @@
-#include "modbus-tcp.h"
+#include <modbus_tcp.h>
 
 #define MAX_REG 250
+#define EXTENSION_LENGHT 4
+
 
 char registers[MAX_REG];
 
@@ -9,7 +11,7 @@ static err_t modbus_incomming_data(void *arg, struct tcp_pcb *pcb, struct pbuf *
     int j;
     int len;
     int lenght;
-    char extention[4];
+    char extention[EXTENSION_LENGHT];
     char *pc;
     char *textstring;
     char text[200];