diff --git a/pymodbus/server/base.py b/pymodbus/server/base.py
index 2f5e02bb2..9065abadd 100644
--- a/pymodbus/server/base.py
+++ b/pymodbus/server/base.py
@@ -10,6 +10,8 @@
 from ..logging import Log
 from ..pdu import DecodePDU, ModbusPDU
 from ..pdu.device import ModbusControlBlock, ModbusDeviceIdentification
+from ..simulator import SimDevice
+from ..simulator.simcore import SimCore
 from ..transport import CommParams, ModbusProtocol
 from .requesthandler import ServerRequestHandler
 
@@ -22,7 +24,7 @@ class ModbusBaseServer(ModbusProtocol):
     def __init__(  # pylint: disable=too-many-arguments
         self,
         params: CommParams,
-        context: ModbusServerContext | None,
+        context: ModbusServerContext | SimDevice | list[SimDevice],
         ignore_missing_devices: bool,
         broadcast_enable: bool,
         identity: ModbusDeviceIdentification | None,
@@ -42,7 +44,11 @@ def __init__(  # pylint: disable=too-many-arguments
         if custom_pdu:
             for func in custom_pdu:
                 self.decoder.register(func)
-        self.context = context or ModbusServerContext()
+        self.context: ModbusServerContext | SimCore
+        if isinstance(context, ModbusServerContext):
+            self.context = context
+        else:
+            self.context = SimCore(context)
         self.control = ModbusControlBlock()
         self.ignore_missing_devices = ignore_missing_devices
         self.broadcast_enable = broadcast_enable
diff --git a/pymodbus/server/server.py b/pymodbus/server/server.py
index a2550eaf0..223f24bd6 100644
--- a/pymodbus/server/server.py
+++ b/pymodbus/server/server.py
@@ -7,6 +7,7 @@
 from ..framer import FramerType
 from ..pdu import ModbusPDU
 from ..pdu.device import ModbusDeviceIdentification
+from ..simulator import SimDevice
 from ..transport import CommParams, CommType
 from .base import ModbusBaseServer
 
@@ -20,7 +21,7 @@ class ModbusTcpServer(ModbusBaseServer):
 
     def __init__(  # pylint: disable=too-many-arguments
         self,
-        context: ModbusServerContext,
+        context: ModbusServerContext | SimDevice | list[SimDevice],
         *,
         framer=FramerType.SOCKET,
         identity: ModbusDeviceIdentification | None = None,
@@ -84,7 +85,7 @@ class ModbusTlsServer(ModbusTcpServer):
 
     def __init__(  # pylint: disable=too-many-arguments
         self,
-        context: ModbusServerContext,
+        context: ModbusServerContext | SimDevice | list[SimDevice],
         *,
         framer=FramerType.TLS,
         identity: ModbusDeviceIdentification | None = None,
@@ -155,7 +156,7 @@ class ModbusUdpServer(ModbusBaseServer):
 
     def __init__(  # pylint: disable=too-many-arguments
         self,
-        context: ModbusServerContext,
+        context: ModbusServerContext | SimDevice | list[SimDevice],
         *,
         framer=FramerType.SOCKET,
         identity: ModbusDeviceIdentification | None = None,
@@ -216,7 +217,7 @@ class ModbusSerialServer(ModbusBaseServer):
 
     def __init__(
         self,
-        context: ModbusServerContext,
+        context: ModbusServerContext | SimDevice | list[SimDevice],
         *,
         framer: FramerType = FramerType.RTU,
         ignore_missing_devices: bool = False,
diff --git a/pymodbus/server/startstop.py b/pymodbus/server/startstop.py
index 79a522584..2cf900cf9 100644
--- a/pymodbus/server/startstop.py
+++ b/pymodbus/server/startstop.py
@@ -5,6 +5,7 @@
 from time import sleep
 
 from ..datastore import ModbusServerContext
+from ..simulator import SimDevice
 from .base import ModbusBaseServer
 from .server import (
     ModbusSerialServer,
@@ -15,7 +16,7 @@
 
 
 async def StartAsyncTcpServer(
-    context: ModbusServerContext,
+    context: ModbusServerContext | SimDevice | list[SimDevice],
     **kwargs,
 ) -> None:
     """Start and run a tcp modbus server.
@@ -32,7 +33,7 @@ async def StartAsyncTcpServer(
 
 
 def StartTcpServer(
-    context: ModbusServerContext,
+    context: ModbusServerContext | SimDevice | list[SimDevice],
     **kwargs
 ) -> None:
     """Start and run a modbus TCP server.
@@ -49,7 +50,7 @@ def StartTcpServer(
 
 
 async def StartAsyncTlsServer(
-    context: ModbusServerContext,
+    context: ModbusServerContext | SimDevice | list[SimDevice],
     **kwargs,
 ) -> None:
     """Start and run a tls modbus server.
@@ -66,7 +67,7 @@ async def StartAsyncTlsServer(
 
 
 def StartTlsServer(
-    context: ModbusServerContext,
+    context: ModbusServerContext | SimDevice | list[SimDevice],
     **kwargs
 ) -> None:
     """Start and run a modbus TLS server.
@@ -83,7 +84,7 @@ def StartTlsServer(
 
 
 async def StartAsyncUdpServer(
-    context: ModbusServerContext,
+    context: ModbusServerContext | SimDevice | list[SimDevice],
     **kwargs,
 ) -> None:
     """Start and run a udp modbus server.
@@ -100,7 +101,7 @@ async def StartAsyncUdpServer(
 
 
 def StartUdpServer(
-    context: ModbusServerContext,
+    context: ModbusServerContext | SimDevice | list[SimDevice],
     **kwargs
 ) -> None:
     """Start and run a modbus UDP server.
@@ -117,7 +118,7 @@ def StartUdpServer(
 
 
 async def StartAsyncSerialServer(
-    context: ModbusServerContext,
+    context: ModbusServerContext | SimDevice | list[SimDevice],
     **kwargs,
 ) -> None:
     """Start and run a serial modbus server.
@@ -134,7 +135,7 @@ async def StartAsyncSerialServer(
 
 
 def StartSerialServer(
-    context: ModbusServerContext,
+    context: ModbusServerContext | SimDevice | list[SimDevice],
     **kwargs
 ) -> None:
     """Start and run a modbus serial server.
diff --git a/pymodbus/simulator/simcore.py b/pymodbus/simulator/simcore.py
index 304570eb6..77945327b 100644
--- a/pymodbus/simulator/simcore.py
+++ b/pymodbus/simulator/simcore.py
@@ -5,6 +5,7 @@
 from __future__ import annotations
 
 from ..constants import ExcCodes
+from ..pdu.pdu import unpack_bitstring
 from .simdevice import SimDevice, SimRegs
 
 
@@ -22,10 +23,15 @@ class Runtime:
                         for i in (1, 5, 15)])
 
 
-        def __convert_to_bit(self, block: SimRegs):
+        @classmethod
+        def convert_to_bit(cls, block: SimRegs) -> SimRegs:
             """Convert registers to bits."""
-            new_flags = block[1]
-            new_registers = block[2]
+            new_registers: list[int] = []
+            for entry in block[2]:
+                bool_list = unpack_bitstring(entry.to_bytes(2, byteorder="big"))
+                for x in bool_list:
+                    new_registers.append(1 if x else 0)
+            new_flags: list[int] = [block[1][0]]*len(new_registers)
             return (block[0], new_flags, new_registers)
 
         def __init__(self, device: SimDevice):
@@ -39,8 +45,8 @@ def __init__(self, device: SimDevice):
                 return
             self.shared = False
             self.block: dict[str, SimRegs] = {
-                "c": self.__convert_to_bit(build["c"]),
-                "d":  self.__convert_to_bit(build["d"]),
+                "c": self.convert_to_bit(build["c"]),
+                "d":  self.convert_to_bit(build["d"]),
                 "h": build["h"],
                 "i": build["i"],
             }
diff --git a/test/client/test_client_sync.py b/test/client/test_client_sync.py
index f2bfacc9f..0b7019d18 100755
--- a/test/client/test_client_sync.py
+++ b/test/client/test_client_sync.py
@@ -31,7 +31,9 @@ class TestSyncClientUdp:
 
     def test_basic_syn_udp_bind(self):
         """Test the basic methods for the udp sync client."""
-        ModbusUdpClient("127.0.0.1", source_address=('', 4096))
+        client = ModbusUdpClient("127.0.0.1", source_address=('', 4096))
+        client.connect()
+
 
     def test_basic_syn_udp_client(self):
         """Test the basic methods for the udp sync client."""
diff --git a/test/server/test_base.py b/test/server/test_base.py
index f027936cd..4bec6dcd1 100755
--- a/test/server/test_base.py
+++ b/test/server/test_base.py
@@ -3,8 +3,10 @@
 
 import pytest
 
+from pymodbus.datastore import ModbusServerContext
 from pymodbus.pdu import ReadHoldingRegistersRequest
 from pymodbus.server import ModbusBaseServer
+from pymodbus.simulator import SimData, SimDevice
 from pymodbus.transport import CommParams, CommType
 
 
@@ -22,7 +24,7 @@ async def baseserver(self):
                 reconnect_delay_max=0.0,
                 timeout_connect=0.0,
             ),
-            None,
+            ModbusServerContext(),
             False,
             False,
             None,
@@ -37,6 +39,27 @@ async def baseserver(self):
     async def test_base(self, baseserver):
         """Test __init__."""
 
+    async def test_base_simcore(self):
+        """Test __init___ with SimCore."""
+        ModbusBaseServer(
+            CommParams(
+                comm_type=CommType.TCP,
+                comm_name="server_listener",
+                reconnect_delay=0.0,
+                reconnect_delay_max=0.0,
+                timeout_connect=0.0,
+            ),
+            SimDevice(0, SimData(0)),
+            False,
+            False,
+            None,
+            "socket",
+            None,
+            None,
+            None,
+            [ReadHoldingRegistersRequest],
+        )
+
     async def test_base_serve_forever1(self, baseserver):
         """Test serve_forever."""
         baseserver.listen = mock.AsyncMock(return_value=None)
diff --git a/test/simulator/test_simcore.py b/test/simulator/test_simcore.py
index 9f9be6820..e895079d2 100644
--- a/test/simulator/test_simcore.py
+++ b/test/simulator/test_simcore.py
@@ -48,3 +48,13 @@ async def test_simdcore_set(self, kwargs):
         """Test that simdata can be objects."""
         core = SimCore(devices=SimDevice(0, simdata=self.simdata2))
         await core.async_setValues(**kwargs)
+
+    @pytest.mark.parametrize(("block", "expect"), [
+        ((3, [1], [0xffff]), (3, [1]*16, [1]*16)),
+        ((3, [1], [0x0000]), (3, [1]*16, [0]*16)),
+        ((3, [1], [0xffff, 0xffff]), (3, [1]*32, [1]*32)),
+    ])
+    async def test_simdcore_convert_bit(self, block, expect):
+        """Test that simdata can be objects."""
+        result = SimCore.Runtime.convert_to_bit(block)
+        assert result == expect