diff --git a/debugging_tool/server.py b/debugging_tool/server.py
index 5b62a03..1a02780 100644
--- a/debugging_tool/server.py
+++ b/debugging_tool/server.py
@@ -6,6 +6,7 @@ from datetime import datetime
 import serial
 import uuid
 from collections import deque
+import sys
 
 app = Flask(__name__)
 
@@ -108,16 +109,16 @@ class Message:
 
 
 def serial_reader(shared_data):
-    with serial.Serial('/dev/ttyACM0', 115200, timeout=10) as ser:
+    with serial.Serial('/dev/ttyUSB0', 115200, timeout=10) as ser:
         while True:
             line = ser.readline()
-            print(line.decode('ascii'))
-            if line.startswith(b"message"):
-                line = line.decode('ascii')
-                line = line.strip()
-                parts = line.split(' ')
-                sender = int(parts[1])
-                message = bytes(int(p) for p in parts[2:])
+            print(line)
+            if len(line) == 12:
+                if line == b'BEGIN START\n':
+                    continue
+                sender = int(line[0] << 8 + line[1])
+                size = int(line[2])
+                message = line[3:3+size]
                 received = Message(message, sender, datetime.now(), len(shared_data.messages))
                 shared_data.messages.append(received.serialize())
                 shared_data.last_message_index += 1
diff --git a/debugging_tool/sketch_can_debugger/sketch_can_debugger.ino b/debugging_tool/sketch_can_debugger/sketch_can_debugger.ino
index 1840086..35badc3 100644
--- a/debugging_tool/sketch_can_debugger/sketch_can_debugger.ino
+++ b/debugging_tool/sketch_can_debugger/sketch_can_debugger.ino
@@ -8,7 +8,7 @@ void setup() {
 	mcp2515.setBitrate(CAN_50KBPS);
 	mcp2515.setNormalMode();
 	for (int i = 0; i < 5; i++) {
-		Serial.println("begin");
+		Serial.print("BEGIN START\n"); // 11 bytes plus newline
 		delay(1000);
 	}
 }
@@ -16,12 +16,28 @@ void setup() {
 void loop() {
 	struct can_frame receive_frame;
 	if (mcp2515.readMessage(&receive_frame) == MCP2515::ERROR_OK) {
-		Serial.print("message ");
-		Serial.print(receive_frame.can_id, DEC);
+		Serial.write((byte) (receive_frame.can_id >> 8));
+		Serial.write((byte) (receive_frame.can_id & 0xff));
+		Serial.write((byte) receive_frame.can_dlc);
 		for (int i = 0; i < receive_frame.can_dlc; i++) {
-			Serial.print(" ");
-			Serial.print(receive_frame.data[i], DEC);
+			Serial.write((byte) receive_frame.data[i]);
 		}
-		Serial.print("\n");
+		for (int i = 0; i < (8 - receive_frame.can_dlc); i++) {
+			Serial.write('\0');
+		}
+		Serial.write('\n');
+	}
+	if (Serial.available()) {
+		byte readbuffer[12];
+		if ((Serial.readBytes(readbuffer, 12) != 12) || readbuffer[11] != '\n') {
+			return;
+		}
+		struct can_frame send_frame;
+		send_frame.can_id = (((uint32_t) readbuffer[0]) << 8) | (readbuffer[1]);
+		send_frame.can_dlc = readbuffer[2];
+		for (int i = 0; i < 8; i++) {
+			send_frame.data[i] = readbuffer[3+i];
+		}
+		mcp2515.sendMessage(&send_frame);
 	}
 }