diff --git a/dxl2/connection.py b/dxl2/connection.py
index c6eac27..6a9d17f 100644
--- a/dxl2/connection.py
+++ b/dxl2/connection.py
@@ -1,12 +1,18 @@
 import dynamixel_sdk as sdk
+import glob
 
+def get_ports():
+    a = glob.glob("/dev/ttyUSB*") + glob.gob("/dev/ttyusbserial*")
+    return a[0]
 
 class Connection:
-    def __init__(self, port: str, baudrate: int = 1_000_000):
+    def __init__(self, port: str = None], baudrate: int = 1_000_000):
         self.port = port
         self.port_handler = sdk.PortHandler(port)
         self.baudrate = baudrate
         self.opened = False
+        if port == None:
+            self.ports = get_ports()
 
     def open_port(self) -> bool:
         ret = self.port_handler.openPort()
diff --git a/dxl2/motor.py b/dxl2/motor.py
index f81dcb4..d50bf2b 100644
--- a/dxl2/motor.py
+++ b/dxl2/motor.py
@@ -46,3 +46,4 @@ def read(self, instruction: Instruction) -> int:
             }[width](self.conn.port_handler, self.id, start)
         except KeyError:
             raise NotImplementedError(f"Register width not supported {width}")
+
diff --git a/dxl2/motor_chain.py b/dxl2/motor_chain.py
index 1bf4e5f..aac1050 100644
--- a/dxl2/motor_chain.py
+++ b/dxl2/motor_chain.py
@@ -50,7 +50,12 @@ def write_many_values(self, instruction: Instruction, vals: Dict[int, int]) -> b
                 self.conn.port_handler, self.packet_handler, pos, size
             )
             for k, v in vals.items():
-                if size == 2:
+                if size == 4:
+                    dxl_addparam_result = groupSyncWrite.addParam(
+                        k, util.create4ByteArray(v)
+                    )
+
+                elif size == 2:
                     dxl_addparam_result = groupSyncWrite.addParam(
                         k, util.create2ByteArray(v)
                     )
diff --git a/dxl2/util.py b/dxl2/util.py
index ba4fe56..ca66bcc 100644
--- a/dxl2/util.py
+++ b/dxl2/util.py
@@ -21,3 +21,13 @@ def create2ByteArray(bin_value):
 def create1ByteArray(bin_value):
     byte_array = [DXL_LOBYTE(DXL_LOWORD(bin_value))]
     return byte_array
+
+
+def create4ByteArray(bin_values):
+    byte_array = [
+        DXL_LOBYTE(DXL_LOWORD(bin_value)),
+        DXL_HIBYTE(DXL_LOWORD(bin_value)),
+        DXL_LOBYTE(DXL_HIWORD(bin_value)),
+        DXL_HIBYTE(DXL_HIWORD(bin_value)),
+    ]
+    return byte_array