diff --git a/custom_components/benq_smartboard/benq_smartboard_lib.py b/custom_components/benq_smartboard/benq_smartboard_lib.py
index faab2e9..c01ae3b 100644
--- a/custom_components/benq_smartboard/benq_smartboard_lib.py
+++ b/custom_components/benq_smartboard/benq_smartboard_lib.py
@@ -324,12 +324,9 @@ class BenQSmartBoard:
         self._ensure_connection()
 
         # Protocol format: [length][tv_id][command_type][command_code][value][CR]
-        # Example: 801s!000\r where command_code 21(hex) = !(ASCII)
-        # Length includes the length byte itself: 1 + tv_id(2) + command_type(1) + command_code(1) + value(3) = 8
+        # Length includes the length byte itself
         if len(command_code) != 2:
             raise ValueError("command_code must be 2 ASCII chars (hex).")
-        if len(value) != 3:
-            raise ValueError("value must be 3 ASCII chars.")
 
         # Convert hex command code to ASCII character
         try:
@@ -338,12 +335,14 @@ class BenQSmartBoard:
         except ValueError:
             raise ValueError(f"Invalid hex command code: {command_code}")
 
-        # Length = length_byte(1) + tv_id(2) + command_type(1) + command_code(1) + value(3) = 8 bytes total
-        length_ascii = b'8'
         tv_id_ascii = b'01' 
         command_type_ascii = b's'  # Set command is 's'
         value_ascii = value.encode('ascii')
         
+        # Calculate dynamic length: length_byte(1) + tv_id(2) + command_type(1) + command_code(1) + value(variable)
+        total_length = 1 + len(tv_id_ascii) + len(command_type_ascii) + len(command_code_ascii) + len(value_ascii)
+        length_ascii = str(total_length).encode('ascii')
+        
         try:
             packet = length_ascii + tv_id_ascii + command_type_ascii + command_code_ascii + value_ascii + self.CR
             _log_packet("Sent", packet)
@@ -378,12 +377,13 @@ class BenQSmartBoard:
         except ValueError:
             raise ValueError(f"Invalid hex command code: {command_code}")
 
-        # For get command: length + tv_id + command_type + command_code + CR
-        # Length = length_byte(1) + tv_id(2) + command_type(1) + command_code(1) = 5 bytes total
-        length_ascii = b'5'
         tv_id_ascii = b'01'
         command_type_ascii = b'g'  # Get command is 'g'
         
+        # Calculate dynamic length: length_byte(1) + tv_id(2) + command_type(1) + command_code(1)
+        total_length = 1 + len(tv_id_ascii) + len(command_type_ascii) + len(command_code_ascii)
+        length_ascii = str(total_length).encode('ascii')
+        
         try:
             logging.debug(f"Sending get command: code={command_code}")
             packet = length_ascii + tv_id_ascii + command_type_ascii + command_code_ascii + self.CR
diff --git a/custom_components/benq_smartboard/serial_test.py b/custom_components/benq_smartboard/serial_test.py
index f355493..53f0339 100644
--- a/custom_components/benq_smartboard/serial_test.py
+++ b/custom_components/benq_smartboard/serial_test.py
@@ -50,6 +50,9 @@ def test_serial_connection():
         try:
             print("Expected packet: 801s!000\\r (where 21 hex = ! ASCII, length=8 includes length byte)")
             board.set_power(PowerState.ON)
+            time.sleep(2)
+            board.set_volume(20)
+            board.set_video_source(VideoSource.OPS)
             print("Power OFF command sent successfully!")
         except Exception as e:
             print(f"Failed to set power OFF: {e}")