diff --git a/examples/client_async.py b/examples/client_async.py
index 5325dd8e3..d676194fe 100755
--- a/examples/client_async.py
+++ b/examples/client_async.py
@@ -65,8 +65,6 @@ def setup_async_client(description=None, cmdline=None):
             reconnect_delay=1,
             reconnect_delay_max=10,
             #    retry_on_empty=False,
-            #    close_comm_on_error=False,
-            #    strict=True,
             # TCP setup parameters
             #    source_address=("localhost", 0),
         )
@@ -79,8 +77,6 @@ def setup_async_client(description=None, cmdline=None):
             timeout=args.timeout,
             #    retries=3,
             #    retry_on_empty=False,
-            #    close_comm_on_error=False,
-            #    strict=True,
             # UDP setup parameters
             #    source_address=None,
         )
@@ -92,8 +88,6 @@ def setup_async_client(description=None, cmdline=None):
             timeout=args.timeout,
             #    retries=3,
             #    retry_on_empty=False,
-            #    close_comm_on_error=False,
-            #    strict=True,
             # Serial setup parameters
             baudrate=args.baudrate,
             #    bytesize=8,
diff --git a/pymodbus/client/base.py b/pymodbus/client/base.py
index 19e65fc70..651c16f88 100644
--- a/pymodbus/client/base.py
+++ b/pymodbus/client/base.py
@@ -26,14 +26,287 @@ class ModbusBaseClient(ModbusClientMixin, ModbusProtocol):
 
     Optional parameters:
 
+    :param timeout: Timeout for a request, in seconds.
+    :param retries: Max number of retries per request.
+    :param retry_on_empty: Retry on empty response.
+    :param broadcast_enable: True to treat id 0 as broadcast address.
+    :param reconnect_delay: Minimum delay in seconds.milliseconds before reconnecting.
+    :param reconnect_delay_max: Maximum delay in seconds.milliseconds before reconnecting.
+    :param on_reconnect_callback: Function that will be called just before a reconnection attempt.
+    :param no_resend_on_retry: Do not resend request when retrying due to missing response.
+    :param kwargs: Experimental parameters.
+
+    .. tip::
+        **reconnect_delay** doubles automatically with each unsuccessful connect, from
+        **reconnect_delay** to **reconnect_delay_max**.
+        Set `reconnect_delay=0` to avoid automatic reconnection.
+
+    :mod:`ModbusBaseClient` is normally not referenced outside :mod:`pymodbus`.
+
+    **Application methods, common to all clients**:
+    """
+
+    def __init__(  # pylint: disable=too-many-arguments
+        self,
+        framer: Framer,
+        timeout: float = 3,
+        retries: int = 3,
+        retry_on_empty: bool = False,
+        broadcast_enable: bool = False,
+        reconnect_delay: float = 0.1,
+        reconnect_delay_max: float = 300,
+        on_reconnect_callback: Callable[[], None] | None = None,
+        no_resend_on_retry: bool = False,
+        **kwargs: Any,
+    ) -> None:
+        """Initialize a client instance."""
+        ModbusClientMixin.__init__(self)
+        ModbusProtocol.__init__(
+            self,
+            CommParams(
+                comm_type=kwargs.get("CommType"),
+                comm_name="comm",
+                source_address=kwargs.get("source_address", ("0.0.0.0", 0)),
+                reconnect_delay=reconnect_delay,
+                reconnect_delay_max=reconnect_delay_max,
+                timeout_connect=timeout,
+                host=kwargs.get("host", None),
+                port=kwargs.get("port", 0),
+                sslctx=kwargs.get("sslctx", None),
+                baudrate=kwargs.get("baudrate", None),
+                bytesize=kwargs.get("bytesize", None),
+                parity=kwargs.get("parity", None),
+                stopbits=kwargs.get("stopbits", None),
+                handle_local_echo=kwargs.get("handle_local_echo", False),
+            ),
+            False,
+        )
+        self.on_reconnect_callback = on_reconnect_callback
+        self.retry_on_empty: int = 0
+        self.no_resend_on_retry = no_resend_on_retry
+        self.slaves: list[int] = []
+        self.retries: int = retries
+        self.broadcast_enable = broadcast_enable
+
+        # Common variables.
+        self.framer = FRAMER_NAME_TO_CLASS.get(
+            framer, cast(Type[ModbusFramer], framer)
+        )(ClientDecoder(), self)
+        self.transaction = DictTransactionManager(
+            self, retries=retries, retry_on_empty=retry_on_empty, **kwargs
+        )
+        self.use_udp = False
+        self.state = ModbusTransactionState.IDLE
+        self.last_frame_end: float | None = 0
+        self.silent_interval: float = 0
+
+    # ----------------------------------------------------------------------- #
+    # Client external interface
+    # ----------------------------------------------------------------------- #
+    @property
+    def connected(self) -> bool:
+        """Return state of connection."""
+        return self.is_active()
+
+    def register(self, custom_response_class: ModbusResponse) -> None:
+        """Register a custom response class with the decoder (call **sync**).
+
+        :param custom_response_class: (optional) Modbus response class.
+        :raises MessageRegisterException: Check exception text.
+
+        Use register() to add non-standard responses (like e.g. a login prompt) and
+        have them interpreted automatically.
+        """
+        self.framer.decoder.register(custom_response_class)
+
+    def close(self, reconnect: bool = False) -> None:
+        """Close connection."""
+        if reconnect:
+            self.connection_lost(asyncio.TimeoutError("Server not responding"))
+        else:
+            self.transport_close()
+
+    def idle_time(self) -> float:
+        """Time before initiating next transaction (call **sync**).
+
+        Applications can call message functions without checking idle_time(),
+        this is done automatically.
+        """
+        if self.last_frame_end is None or self.silent_interval is None:
+            return 0
+        return self.last_frame_end + self.silent_interval
+
+    def execute(self, request: ModbusRequest | None = None) -> ModbusResponse:
+        """Execute request and get response (call **sync/async**).
+
+        :param request: The request to process
+        :returns: The result of the request execution
+        :raises ConnectionException: Check exception text.
+        """
+        if not self.transport:
+            raise ConnectionException(f"Not connected[{self!s}]")
+        return self.async_execute(request)
+
+    # ----------------------------------------------------------------------- #
+    # Merged client methods
+    # ----------------------------------------------------------------------- #
+    async def async_execute(self, request=None):
+        """Execute requests asynchronously."""
+        request.transaction_id = self.transaction.getNextTID()
+        packet = self.framer.buildPacket(request)
+
+        count = 0
+        while count <= self.retries:
+            if not count or not self.no_resend_on_retry:
+                self.transport_send(packet)
+            if self.broadcast_enable and not request.slave_id:
+                resp = b"Broadcast write sent - no response expected"
+                break
+            try:
+                req = self._build_response(request.transaction_id)
+                resp = await asyncio.wait_for(
+                    req, timeout=self.comm_params.timeout_connect
+                )
+                break
+            except asyncio.exceptions.TimeoutError:
+                count += 1
+        if count > self.retries:
+            self.close(reconnect=True)
+            raise ModbusIOException(
+                f"ERROR: No response received after {self.retries} retries"
+            )
+
+        return resp
+
+    def callback_data(self, data: bytes, addr: tuple | None = None) -> int:
+        """Handle received data.
+
+        returns number of bytes consumed
+        """
+        self.framer.processIncomingPacket(data, self._handle_response, slave=0)
+        return len(data)
+
+    def callback_disconnected(self, _reason: Exception | None) -> None:
+        """Handle lost connection."""
+        for tid in list(self.transaction):
+            self.raise_future(
+                self.transaction.getTransaction(tid),
+                ConnectionException("Connection lost during request"),
+            )
+
+    async def connect(self):
+        """Connect to the modbus remote host."""
+
+    def raise_future(self, my_future, exc):
+        """Set exception of a future if not done."""
+        if not my_future.done():
+            my_future.set_exception(exc)
+
+    def _handle_response(self, reply, **_kwargs):
+        """Handle the processed response and link to correct deferred."""
+        if reply is not None:
+            tid = reply.transaction_id
+            if handler := self.transaction.getTransaction(tid):
+                if not handler.done():
+                    handler.set_result(reply)
+            else:
+                Log.debug("Unrequested message: {}", reply, ":str")
+
+    def _build_response(self, tid):
+        """Return a deferred response for the current request."""
+        my_future = asyncio.Future()
+        if not self.transport:
+            self.raise_future(my_future, ConnectionException("Client is not connected"))
+        else:
+            self.transaction.addTransaction(my_future, tid)
+        return my_future
+
+    # ----------------------------------------------------------------------- #
+    # Internal methods
+    # ----------------------------------------------------------------------- #
+    def send(self, request):
+        """Send request.
+
+        :meta private:
+        """
+        if self.state != ModbusTransactionState.RETRYING:
+            Log.debug('New Transaction state "SENDING"')
+            self.state = ModbusTransactionState.SENDING
+        return request
+
+    def recv(self, size):
+        """Receive data.
+
+        :meta private:
+        """
+        return size
+
+    @classmethod
+    def _get_address_family(cls, address):
+        """Get the correct address family."""
+        try:
+            _ = socket.inet_pton(socket.AF_INET6, address)
+        except OSError:  # not a valid ipv6 address
+            return socket.AF_INET
+        return socket.AF_INET6
+
+    # ----------------------------------------------------------------------- #
+    # The magic methods
+    # ----------------------------------------------------------------------- #
+    def __enter__(self):
+        """Implement the client with enter block.
+
+        :returns: The current instance of the client
+        :raises ConnectionException:
+        """
+        if not self.connect():
+            raise ConnectionException(f"Failed to connect[{self.__str__()}]")
+        return self
+
+    async def __aenter__(self):
+        """Implement the client with enter block.
+
+        :returns: The current instance of the client
+        :raises ConnectionException:
+        """
+        if not await self.connect():
+            raise ConnectionException(f"Failed to connect[{self.__str__()}]")
+        return self
+
+    def __exit__(self, klass, value, traceback):
+        """Implement the client with exit block."""
+        self.close()
+
+    async def __aexit__(self, klass, value, traceback):
+        """Implement the client with exit block."""
+        self.close()
+
+    def __str__(self):
+        """Build a string representation of the connection.
+
+        :returns: The string representation
+        """
+        return (
+            f"{self.__class__.__name__} {self.comm_params.host}:{self.comm_params.port}"
+        )
+
+class ModbusBaseSyncClient(ModbusClientMixin, ModbusProtocol):
+    """**ModbusBaseClient**.
+
+    Fixed parameters:
+
+    :param framer: Framer enum name
+
+    Optional parameters:
+
     :param timeout: Timeout for a request, in seconds.
     :param retries: Max number of retries per request.
     :param retry_on_empty: Retry on empty response.
     :param close_comm_on_error: Close connection on error.
     :param strict: Strict timing, 1.5 character between requests.
     :param broadcast_enable: True to treat id 0 as broadcast address.
-    :param reconnect_delay: Minimum delay in milliseconds before reconnecting.
-    :param reconnect_delay_max: Maximum delay in milliseconds before reconnecting.
+    :param reconnect_delay: Minimum delay in seconds.milliseconds before reconnecting.
+    :param reconnect_delay_max: Maximum delay in seconds.milliseconds before reconnecting.
     :param on_reconnect_callback: Function that will be called just before a reconnection attempt.
     :param no_resend_on_retry: Do not resend request when retrying due to missing response.
     :param kwargs: Experimental parameters.
@@ -73,38 +346,33 @@ def __init__(  # pylint: disable=too-many-arguments
         strict: bool = True,
         broadcast_enable: bool = False,
         reconnect_delay: float = 0.1,
-        reconnect_delay_max: float = 300,
+        reconnect_delay_max: float = 300.0,
         on_reconnect_callback: Callable[[], None] | None = None,
         no_resend_on_retry: bool = False,
         **kwargs: Any,
     ) -> None:
         """Initialize a client instance."""
         ModbusClientMixin.__init__(self)
-        self.use_sync = kwargs.get("use_sync", False)
-        setup_params = CommParams(
-            comm_type=kwargs.get("CommType"),
-            comm_name="comm",
-            source_address=kwargs.get("source_address", ("0.0.0.0", 0)),
-            reconnect_delay=reconnect_delay,
-            reconnect_delay_max=reconnect_delay_max,
-            timeout_connect=timeout,
-            host=kwargs.get("host", None),
-            port=kwargs.get("port", 0),
-            sslctx=kwargs.get("sslctx", None),
-            baudrate=kwargs.get("baudrate", None),
-            bytesize=kwargs.get("bytesize", None),
-            parity=kwargs.get("parity", None),
-            stopbits=kwargs.get("stopbits", None),
-            handle_local_echo=kwargs.get("handle_local_echo", False),
+        ModbusProtocol.__init__(
+            self,
+            CommParams(
+                comm_type=kwargs.get("CommType"),
+                comm_name="comm",
+                source_address=kwargs.get("source_address", ("0.0.0.0", 0)),
+                reconnect_delay=reconnect_delay,
+                reconnect_delay_max=reconnect_delay_max,
+                timeout_connect=timeout,
+                host=kwargs.get("host", None),
+                port=kwargs.get("port", 0),
+                sslctx=kwargs.get("sslctx", None),
+                baudrate=kwargs.get("baudrate", None),
+                bytesize=kwargs.get("bytesize", None),
+                parity=kwargs.get("parity", None),
+                stopbits=kwargs.get("stopbits", None),
+                handle_local_echo=kwargs.get("handle_local_echo", False),
+            ),
+            False,
         )
-        if not self.use_sync:
-            ModbusProtocol.__init__(
-                self,
-                setup_params,
-                False,
-            )
-        else:
-            self.comm_params = setup_params
         self.params = self._params()
         self.params.retries = int(retries)
         self.params.retry_on_empty = bool(retry_on_empty)
@@ -172,13 +440,9 @@ def execute(self, request: ModbusRequest | None = None) -> ModbusResponse:
         :returns: The result of the request execution
         :raises ConnectionException: Check exception text.
         """
-        if self.use_sync:
-            if not self.connect():
-                raise ConnectionException(f"Failed to connect[{self!s}]")
-            return self.transaction.execute(request)
-        if not self.transport:
-            raise ConnectionException(f"Not connected[{self!s}]")
-        return self.async_execute(request)
+        if not self.connect():
+            raise ConnectionException(f"Failed to connect[{self!s}]")
+        return self.transaction.execute(request)
 
     # ----------------------------------------------------------------------- #
     # Merged client methods
diff --git a/pymodbus/client/serial.py b/pymodbus/client/serial.py
index 39e1e4417..6f3701543 100644
--- a/pymodbus/client/serial.py
+++ b/pymodbus/client/serial.py
@@ -6,7 +6,7 @@
 from functools import partial
 from typing import Any
 
-from pymodbus.client.base import ModbusBaseClient
+from pymodbus.client.base import ModbusBaseClient, ModbusBaseSyncClient
 from pymodbus.exceptions import ConnectionException
 from pymodbus.framer import Framer
 from pymodbus.logging import Log
@@ -43,11 +43,9 @@ class AsyncModbusSerialClient(ModbusBaseClient, asyncio.Protocol):
     :param timeout: Timeout for a request, in seconds.
     :param retries: Max number of retries per request.
     :param retry_on_empty: Retry on empty response.
-    :param close_comm_on_error: Close connection on error.
-    :param strict: Strict timing, 1.5 character between requests.
     :param broadcast_enable: True to treat id 0 as broadcast address.
-    :param reconnect_delay: Minimum delay in milliseconds before reconnecting.
-    :param reconnect_delay_max: Maximum delay in milliseconds before reconnecting.
+    :param reconnect_delay: Minimum delay in seconds.milliseconds before reconnecting.
+    :param reconnect_delay_max: Maximum delay in seconds.milliseconds before reconnecting.
     :param on_reconnect_callback: Function that will be called just before a reconnection attempt.
     :param no_resend_on_retry: Do not resend request when retrying due to missing response.
     :param kwargs: Experimental parameters.
@@ -106,7 +104,7 @@ def close(self, reconnect: bool = False) -> None:
         super().close(reconnect=reconnect)
 
 
-class ModbusSerialClient(ModbusBaseClient):
+class ModbusSerialClient(ModbusBaseSyncClient):
     """**ModbusSerialClient**.
 
     Fixed parameters:
@@ -130,8 +128,8 @@ class ModbusSerialClient(ModbusBaseClient):
     :param close_comm_on_error: Close connection on error.
     :param strict: Strict timing, 1.5 character between requests.
     :param broadcast_enable: True to treat id 0 as broadcast address.
-    :param reconnect_delay: Minimum delay in milliseconds before reconnecting.
-    :param reconnect_delay_max: Maximum delay in milliseconds before reconnecting.
+    :param reconnect_delay: Minimum delay in seconds.milliseconds before reconnecting.
+    :param reconnect_delay_max: Maximum delay in seconds.milliseconds before reconnecting.
     :param on_reconnect_callback: Function that will be called just before a reconnection attempt.
     :param no_resend_on_retry: Do not resend request when retrying due to missing response.
     :param kwargs: Experimental parameters.
@@ -167,7 +165,6 @@ def __init__(
         **kwargs: Any,
     ) -> None:
         """Initialize Modbus Serial Client."""
-        kwargs["use_sync"] = True
         super().__init__(
             framer,
             CommType=CommType.SERIAL,
diff --git a/pymodbus/client/tcp.py b/pymodbus/client/tcp.py
index 9a196e75a..eb9ee0873 100644
--- a/pymodbus/client/tcp.py
+++ b/pymodbus/client/tcp.py
@@ -7,7 +7,7 @@
 import time
 from typing import Any
 
-from pymodbus.client.base import ModbusBaseClient
+from pymodbus.client.base import ModbusBaseClient, ModbusBaseSyncClient
 from pymodbus.exceptions import ConnectionException
 from pymodbus.framer import Framer
 from pymodbus.logging import Log
@@ -33,11 +33,9 @@ class AsyncModbusTcpClient(ModbusBaseClient, asyncio.Protocol):
     :param timeout: Timeout for a request, in seconds.
     :param retries: Max number of retries per request.
     :param retry_on_empty: Retry on empty response.
-    :param close_comm_on_error: Close connection on error.
-    :param strict: Strict timing, 1.5 character between requests.
     :param broadcast_enable: True to treat id 0 as broadcast address.
-    :param reconnect_delay: Minimum delay in milliseconds before reconnecting.
-    :param reconnect_delay_max: Maximum delay in milliseconds before reconnecting.
+    :param reconnect_delay: Minimum delay in seconds.milliseconds before reconnecting.
+    :param reconnect_delay_max: Maximum delay in seconds.milliseconds before reconnecting.
     :param on_reconnect_callback: Function that will be called just before a reconnection attempt.
     :param no_resend_on_retry: Do not resend request when retrying due to missing response.
     :param kwargs: Experimental parameters.
@@ -77,7 +75,6 @@ def __init__(
             port=port,
             **kwargs,
         )
-        self.params.source_address = source_address
 
     async def connect(self) -> bool:
         """Initiate connection to start client."""
@@ -94,7 +91,7 @@ def close(self, reconnect: bool = False) -> None:
         super().close(reconnect=reconnect)
 
 
-class ModbusTcpClient(ModbusBaseClient):
+class ModbusTcpClient(ModbusBaseSyncClient):
     """**ModbusTcpClient**.
 
     Fixed parameters:
@@ -115,8 +112,8 @@ class ModbusTcpClient(ModbusBaseClient):
     :param close_comm_on_error: Close connection on error.
     :param strict: Strict timing, 1.5 character between requests.
     :param broadcast_enable: True to treat id 0 as broadcast address.
-    :param reconnect_delay: Minimum delay in milliseconds before reconnecting.
-    :param reconnect_delay_max: Maximum delay in milliseconds before reconnecting.
+    :param reconnect_delay: Minimum delay in seconds.milliseconds before reconnecting.
+    :param reconnect_delay_max: Maximum delay in seconds.milliseconds before reconnecting.
     :param on_reconnect_callback: Function that will be called just before a reconnection attempt.
     :param no_resend_on_retry: Do not resend request when retrying due to missing response.
     :param kwargs: Experimental parameters.
@@ -148,7 +145,6 @@ def __init__(
         """Initialize Modbus TCP Client."""
         if "CommType" not in kwargs:
             kwargs["CommType"] = CommType.TCP
-        kwargs["use_sync"] = True
         super().__init__(
             framer,
             host=host,
diff --git a/pymodbus/client/tls.py b/pymodbus/client/tls.py
index 1dbd54031..d59ca3b8a 100644
--- a/pymodbus/client/tls.py
+++ b/pymodbus/client/tls.py
@@ -34,11 +34,9 @@ class AsyncModbusTlsClient(AsyncModbusTcpClient):
     :param timeout: Timeout for a request, in seconds.
     :param retries: Max number of retries per request.
     :param retry_on_empty: Retry on empty response.
-    :param close_comm_on_error: Close connection on error.
-    :param strict: Strict timing, 1.5 character between requests.
     :param broadcast_enable: True to treat id 0 as broadcast address.
-    :param reconnect_delay: Minimum delay in milliseconds before reconnecting.
-    :param reconnect_delay_max: Maximum delay in milliseconds before reconnecting.
+    :param reconnect_delay: Minimum delay in seconds.milliseconds before reconnecting.
+    :param reconnect_delay_max: Maximum delay in seconds.milliseconds before reconnecting.
     :param on_reconnect_callback: Function that will be called just before a reconnection attempt.
     :param no_resend_on_retry: Do not resend request when retrying due to missing response.
     :param kwargs: Experimental parameters.
@@ -81,7 +79,7 @@ def __init__(
             ),
             **kwargs,
         )
-        self.params.server_hostname = server_hostname
+        self.server_hostname = server_hostname
 
     async def connect(self) -> bool:
         """Initiate connection to start client."""
@@ -121,8 +119,8 @@ class ModbusTlsClient(ModbusTcpClient):
     :param close_comm_on_error: Close connection on error.
     :param strict: Strict timing, 1.5 character between requests.
     :param broadcast_enable: True to treat id 0 as broadcast address.
-    :param reconnect_delay: Minimum delay in milliseconds before reconnecting.
-    :param reconnect_delay_max: Maximum delay in milliseconds before reconnecting.
+    :param reconnect_delay: Minimum delay in seconds.milliseconds before reconnecting.
+    :param reconnect_delay_max: Maximum delay in seconds.milliseconds before reconnecting.
     :param on_reconnect_callback: Function that will be called just before a reconnection attempt.
     :param no_resend_on_retry: Do not resend request when retrying due to missing response.
     :param kwargs: Experimental parameters.
diff --git a/pymodbus/client/udp.py b/pymodbus/client/udp.py
index 885c6bae8..7b0c8b36c 100644
--- a/pymodbus/client/udp.py
+++ b/pymodbus/client/udp.py
@@ -5,7 +5,7 @@
 import socket
 from typing import Any
 
-from pymodbus.client.base import ModbusBaseClient
+from pymodbus.client.base import ModbusBaseClient, ModbusBaseSyncClient
 from pymodbus.exceptions import ConnectionException
 from pymodbus.framer import Framer
 from pymodbus.logging import Log
@@ -35,11 +35,9 @@ class AsyncModbusUdpClient(
     :param timeout: Timeout for a request, in seconds.
     :param retries: Max number of retries per request.
     :param retry_on_empty: Retry on empty response.
-    :param close_comm_on_error: Close connection on error.
-    :param strict: Strict timing, 1.5 character between requests.
     :param broadcast_enable: True to treat id 0 as broadcast address.
-    :param reconnect_delay: Minimum delay in milliseconds before reconnecting.
-    :param reconnect_delay_max: Maximum delay in milliseconds before reconnecting.
+    :param reconnect_delay: Minimum delay in seconds.milliseconds before reconnecting.
+    :param reconnect_delay_max: Maximum delay in seconds.milliseconds before reconnecting.
     :param on_reconnect_callback: Function that will be called just before a reconnection attempt.
     :param no_resend_on_retry: Do not resend request when retrying due to missing response.
     :param kwargs: Experimental parameters.
@@ -77,7 +75,7 @@ def __init__(
             port=port,
             **kwargs,
         )
-        self.params.source_address = source_address
+        self.source_address = source_address
 
     @property
     def connected(self):
@@ -98,7 +96,7 @@ async def connect(self) -> bool:
         return await self.transport_connect()
 
 
-class ModbusUdpClient(ModbusBaseClient):
+class ModbusUdpClient(ModbusBaseSyncClient):
     """**ModbusUdpClient**.
 
     Fixed parameters:
@@ -119,8 +117,8 @@ class ModbusUdpClient(ModbusBaseClient):
     :param close_comm_on_error: Close connection on error.
     :param strict: Strict timing, 1.5 character between requests.
     :param broadcast_enable: True to treat id 0 as broadcast address.
-    :param reconnect_delay: Minimum delay in milliseconds before reconnecting.
-    :param reconnect_delay_max: Maximum delay in milliseconds before reconnecting.
+    :param reconnect_delay: Minimum delay in seconds.milliseconds before reconnecting.
+    :param reconnect_delay_max: Maximum delay in seconds.milliseconds before reconnecting.
     :param on_reconnect_callback: Function that will be called just before a reconnection attempt.
     :param no_resend_on_retry: Do not resend request when retrying due to missing response.
     :param kwargs: Experimental parameters.
@@ -150,7 +148,6 @@ def __init__(
         **kwargs: Any,
     ) -> None:
         """Initialize Modbus UDP Client."""
-        kwargs["use_sync"] = True
         super().__init__(
             framer,
             port=port,