diff --git a/src/tmtccmd/com/__init__.py b/src/tmtccmd/com/__init__.py
index 2391c185..20b2ff33 100644
--- a/src/tmtccmd/com/__init__.py
+++ b/src/tmtccmd/com/__init__.py
@@ -61,7 +61,7 @@ def close(self, args: Any = 0):
         """
 
     @abstractmethod
-    def send(self, data: bytes):
+    def send(self, data: bytes | bytearray):
         """Send raw data.
 
         :raises SendError: Sending failed for some reason.
diff --git a/src/tmtccmd/com/dummy.py b/src/tmtccmd/com/dummy.py
index 7a7edb7f..30f0e51d 100644
--- a/src/tmtccmd/com/dummy.py
+++ b/src/tmtccmd/com/dummy.py
@@ -136,6 +136,6 @@ def data_available(self, timeout: float = 0, parameters: any = 0):
     def receive(self, parameters: any = 0) -> List[bytes]:
         return self.dummy_handler.receive_reply_package()
 
-    def send(self, data: bytes):
+    def send(self, data: bytes | bytearray):
         if data is not None:
             self.dummy_handler.insert_telecommand(data)
diff --git a/src/tmtccmd/com/serial_cobs.py b/src/tmtccmd/com/serial_cobs.py
index f8e77889..84d96fda 100644
--- a/src/tmtccmd/com/serial_cobs.py
+++ b/src/tmtccmd/com/serial_cobs.py
@@ -49,7 +49,7 @@ def close(self, args: any = None) -> None:
         self.__reception_thread.join(0.4)
         super().close_port()
 
-    def send(self, data: bytes):
+    def send(self, data: bytes | bytearray):
         encoded = bytearray([0])
         encoded.extend(cobs.encode(data))
         encoded.append(0)
diff --git a/src/tmtccmd/com/serial_dle.py b/src/tmtccmd/com/serial_dle.py
index 8a8a84df..932bd9a2 100644
--- a/src/tmtccmd/com/serial_dle.py
+++ b/src/tmtccmd/com/serial_dle.py
@@ -87,7 +87,7 @@ def close(self, args: any = None) -> None:
         self.__reception_thread.join(0.4)
         super().close_port()
 
-    def send(self, data: bytes):
+    def send(self, data: bytes | bytearray):
         encoded_data = self.__encoder.encode(source_packet=data, add_stx_etx=True)
         self.serial.write(encoded_data)
 
diff --git a/src/tmtccmd/com/tcp.py b/src/tmtccmd/com/tcp.py
index 099926fd..ade151f4 100644
--- a/src/tmtccmd/com/tcp.py
+++ b/src/tmtccmd/com/tcp.py
@@ -123,7 +123,7 @@ def close(self, args: any = None) -> None:
                 self.__connected = False
         self.__tcp_socket = None
 
-    def send(self, data: bytes):
+    def send(self, data: bytes | bytearray):
         self.__tc_queue.put(data)
 
     def receive(self, poll_timeout: float = 0) -> List[bytes]:
diff --git a/src/tmtccmd/com/udp.py b/src/tmtccmd/com/udp.py
index 8e1156a0..9878c0cc 100644
--- a/src/tmtccmd/com/udp.py
+++ b/src/tmtccmd/com/udp.py
@@ -64,7 +64,7 @@ def close(self, args: any = None) -> None:
         if self.udp_socket is not None:
             self.udp_socket.close()
 
-    def send(self, data: bytes):
+    def send(self, data: bytes | bytearray):
         if self.udp_socket is None:
             return
         bytes_sent = self.udp_socket.sendto(data, self.send_address.to_tuple)