diff --git a/examples/client_custom_msg.py b/examples/client_custom_msg.py
index 395370a21..67be8d0e1 100755
--- a/examples/client_custom_msg.py
+++ b/examples/client_custom_msg.py
@@ -38,7 +38,7 @@ class CustomModbusPDU(ModbusPDU):
 
     def __init__(self, values=None, slave=1, transaction=0):
         """Initialize."""
-        super().__init__(slave_id=slave, transaction_id=transaction)
+        super().__init__(dev_id=slave, transaction_id=transaction)
         self.values = values or []
 
     def encode(self):
@@ -70,7 +70,7 @@ class CustomRequest(ModbusPDU):
 
     def __init__(self, address=None, slave=1, transaction=0):
         """Initialize."""
-        super().__init__(slave_id=slave, transaction_id=transaction)
+        super().__init__(dev_id=slave, transaction_id=transaction)
         self.address = address
         self.count = 16
 
@@ -105,7 +105,7 @@ def __init__(self, address, slave=1, transaction=0):
 
         :param address: The address to start reading from
         """
-        super().__init__(address=address, count=16, slave_id=slave, transaction_id=transaction)
+        super().__init__(address=address, count=16, dev_id=slave, transaction_id=transaction)
 
 
 # --------------------------------------------------------------------------- #
diff --git a/examples/modbus_forwarder.py b/examples/modbus_forwarder.py
index 7933f1bb3..2a98e16da 100755
--- a/examples/modbus_forwarder.py
+++ b/examples/modbus_forwarder.py
@@ -56,7 +56,7 @@ async def run_forwarder(args):
     )
     args.client.connect()
     assert args.client.connected
-    # If required to communicate with a specified client use slave=<slave_id>
+    # If required to communicate with a specified client use slave=<device id>
     # in RemoteSlaveContext
     # For e.g to forward the requests to slave with slave address 1 use
     # store = RemoteSlaveContext(client, slave=1)
diff --git a/examples/server_async.py b/examples/server_async.py
index 86166341d..d205be648 100755
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -152,7 +152,7 @@ async def run_async_server(args):
             # custom_functions=[],  # allow custom handling
             framer=args.framer,  # The framer strategy to use
             # ignore_missing_slaves=True,  # ignore request to a missing slave
-            # broadcast_enable=False,  # treat slave_id 0 as broadcast address,
+            # broadcast_enable=False,  # treat slave 0 as broadcast address,
             # timeout=1,  # waiting time for request to complete
         )
     elif args.comm == "udp":
@@ -167,7 +167,7 @@ async def run_async_server(args):
             # custom_functions=[],  # allow custom handling
             framer=args.framer,  # The framer strategy to use
             # ignore_missing_slaves=True,  # ignore request to a missing slave
-            # broadcast_enable=False,  # treat slave_id 0 as broadcast address,
+            # broadcast_enable=False,  # treat slave 0 as broadcast address,
             # timeout=1,  # waiting time for request to complete
         )
     elif args.comm == "serial":
@@ -186,7 +186,7 @@ async def run_async_server(args):
             baudrate=args.baudrate,  # The baud rate to use for the serial device
             # handle_local_echo=False,  # Handle local echo of the USB-to-RS485 adaptor
             # ignore_missing_slaves=True,  # ignore request to a missing slave
-            # broadcast_enable=False,  # treat slave_id 0 as broadcast address,
+            # broadcast_enable=False,  # treat slave 0 as broadcast address,
         )
     elif args.comm == "tls":
         address = (args.host if args.host else "", args.port if args.port else None)
@@ -207,7 +207,7 @@ async def run_async_server(args):
             ),  # The key file path for TLS (used if sslctx is None)
             # password="none",  # The password for for decrypting the private key file
             # ignore_missing_slaves=True,  # ignore request to a missing slave
-            # broadcast_enable=False,  # treat slave_id 0 as broadcast address,
+            # broadcast_enable=False,  # treat slave 0 as broadcast address,
             # timeout=1,  # waiting time for request to complete
         )
     return server
diff --git a/examples/server_sync.py b/examples/server_sync.py
index 871acd5f6..7c735b2d2 100755
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -78,7 +78,7 @@ def run_sync_server(args):
             # custom_functions=[],  # allow custom handling
             framer=args.framer,  # The framer strategy to use
             # ignore_missing_slaves=True,  # ignore request to a missing slave
-            # broadcast_enable=False,  # treat slave_id 0 as broadcast address,
+            # broadcast_enable=False,  # treat slave 0 as broadcast address,
             # timeout=1,  # waiting time for request to complete
         )
     elif args.comm == "udp":
@@ -90,7 +90,7 @@ def run_sync_server(args):
             # custom_functions=[],  # allow custom handling
             framer=args.framer,  # The framer strategy to use
             # ignore_missing_slaves=True,  # ignore request to a missing slave
-            # broadcast_enable=False,  # treat slave_id 0 as broadcast address,
+            # broadcast_enable=False,  # treat slave 0 as broadcast address,
             # timeout=1,  # waiting time for request to complete
         )
     elif args.comm == "serial":
@@ -109,7 +109,7 @@ def run_sync_server(args):
             baudrate=args.baudrate,  # The baud rate to use for the serial device
             # handle_local_echo=False,  # Handle local echo of the USB-to-RS485 adaptor
             # ignore_missing_slaves=True,  # ignore request to a missing slave
-            # broadcast_enable=False,  # treat slave_id 0 as broadcast address,
+            # broadcast_enable=False,  # treat slave 0 as broadcast address,
         )
     elif args.comm == "tls":
         address = ("", args.port) if args.port else None
@@ -130,7 +130,7 @@ def run_sync_server(args):
             ),  # The key file path for TLS (used if sslctx is None)
             # password=None,  # The password for for decrypting the private key file
             # ignore_missing_slaves=True,  # ignore request to a missing slave
-            # broadcast_enable=False,  # treat slave_id 0 as broadcast address,
+            # broadcast_enable=False,  # treat slave 0 as broadcast address,
             # timeout=1,  # waiting time for request to complete
         )
     return server
diff --git a/pymodbus/client/mixin.py b/pymodbus/client/mixin.py
index b40196eb3..e16b7e8ec 100644
--- a/pymodbus/client/mixin.py
+++ b/pymodbus/client/mixin.py
@@ -67,7 +67,7 @@ def read_coils(self, address: int, *, count: int = 1, slave: int = 1, no_respons
 
         Coils are addressed as 0-N (Note some device manuals uses 1-N, assuming 1==0).
         """
-        return self.execute(no_response_expected, pdu_bit.ReadCoilsRequest(address=address, count=count, slave_id=slave))
+        return self.execute(no_response_expected, pdu_bit.ReadCoilsRequest(address=address, count=count, dev_id=slave))
 
     def read_discrete_inputs(self,
                              address: int,
@@ -87,7 +87,7 @@ def read_discrete_inputs(self,
 
         Discrete Inputs are addressed as 0-N (Note some device manuals uses 1-N, assuming 1==0).
         """
-        pdu = pdu_bit.ReadDiscreteInputsRequest(address=address, count=count, slave_id=slave)
+        pdu = pdu_bit.ReadDiscreteInputsRequest(address=address, count=count, dev_id=slave)
         return self.execute(no_response_expected, pdu)
 
     def read_holding_registers(self,
@@ -111,7 +111,7 @@ def read_holding_registers(self,
         Registers are addressed starting at zero.
         Therefore devices that specify 1-16 are addressed as 0-15.
         """
-        return self.execute(no_response_expected, pdu_reg.ReadHoldingRegistersRequest(address=address, count=count, slave_id=slave))
+        return self.execute(no_response_expected, pdu_reg.ReadHoldingRegistersRequest(address=address, count=count, dev_id=slave))
 
     def read_input_registers(self,
                              address: int,
@@ -134,7 +134,7 @@ def read_input_registers(self,
         Registers are addressed starting at zero.
         Therefore devices that specify 1-16 are addressed as 0-15.
         """
-        return self.execute(no_response_expected, pdu_reg.ReadInputRegistersRequest(address=address, count=count, slave_id=slave))
+        return self.execute(no_response_expected, pdu_reg.ReadInputRegistersRequest(address=address, count=count, dev_id=slave))
 
     def write_coil(self, address: int, value: bool, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Write single coil (code 0x05).
@@ -149,7 +149,7 @@ def write_coil(self, address: int, value: bool, *, slave: int = 1, no_response_e
 
         Coils are addressed as 0-N (Note some device manuals uses 1-N, assuming 1==0).
         """
-        pdu = pdu_bit.WriteSingleCoilRequest(address=address, bits=[value], slave_id=slave)
+        pdu = pdu_bit.WriteSingleCoilRequest(address=address, bits=[value], dev_id=slave)
         return self.execute(no_response_expected, pdu)
 
     def write_register(self, address: int, value: int, *, slave: int = 1, no_response_expected: bool = False) -> T:
@@ -168,7 +168,7 @@ def write_register(self, address: int, value: int, *, slave: int = 1, no_respons
         Registers are addressed starting at zero. Therefore register
         numbered 1 is addressed as 0.
         """
-        return self.execute(no_response_expected, pdu_reg.WriteSingleRegisterRequest(address=address, registers=[value], slave_id=slave))
+        return self.execute(no_response_expected, pdu_reg.WriteSingleRegisterRequest(address=address, registers=[value], dev_id=slave))
 
     def read_exception_status(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Read Exception Status (code 0x07).
@@ -183,7 +183,7 @@ def read_exception_status(self, *, slave: int = 1, no_response_expected: bool =
         accessing this information, because the Exception Output references are
         known (no output reference is needed in the function).
         """
-        return self.execute(no_response_expected, pdu_other_msg.ReadExceptionStatusRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_other_msg.ReadExceptionStatusRequest(dev_id=slave))
 
     def diag_query_data(self, msg: bytes, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose query data (code 0x08 sub 0x00).
@@ -197,7 +197,7 @@ def diag_query_data(self, msg: bytes, *, slave: int = 1, no_response_expected: b
         in the response. The entire response message should be identical to the
         request.
         """
-        return self.execute(no_response_expected, pdu_diag.ReturnQueryDataRequest(msg, slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ReturnQueryDataRequest(msg, dev_id=slave))
 
     def diag_restart_communication(self, toggle: bool, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose restart communication (code 0x08 sub 0x01).
@@ -215,7 +215,7 @@ def diag_restart_communication(self, toggle: bool, *, slave: int = 1, no_respons
         occurs before the restart is update_datastored.
         """
         msg = ModbusStatus.ON if toggle else ModbusStatus.OFF
-        return self.execute(no_response_expected, pdu_diag.RestartCommunicationsOptionRequest(message=msg, slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.RestartCommunicationsOptionRequest(message=msg, dev_id=slave))
 
     def diag_read_diagnostic_register(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose read diagnostic register (code 0x08 sub 0x02).
@@ -226,7 +226,7 @@ def diag_read_diagnostic_register(self, *, slave: int = 1, no_response_expected:
 
         The contents of the remote device's 16-bit diagnostic register are returned in the response.
         """
-        return self.execute(no_response_expected, pdu_diag.ReturnDiagnosticRegisterRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ReturnDiagnosticRegisterRequest(dev_id=slave))
 
     def diag_change_ascii_input_delimeter(self, *, delimiter: int = 0x0a, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose change ASCII input delimiter (code 0x08 sub 0x03).
@@ -241,7 +241,7 @@ def diag_change_ascii_input_delimeter(self, *, delimiter: int = 0x0a, slave: int
         character). This function is useful in cases of a Line Feed is not
         required at the end of ASCII messages.
         """
-        return self.execute(no_response_expected, pdu_diag.ChangeAsciiInputDelimiterRequest(message=delimiter, slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ChangeAsciiInputDelimiterRequest(message=delimiter, dev_id=slave))
 
     def diag_force_listen_only(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose force listen only (code 0x08 sub 0x04).
@@ -256,7 +256,7 @@ def diag_force_listen_only(self, *, slave: int = 1, no_response_expected: bool =
         allowing them to continue communicating without interruption from the
         addressed remote device. No response is returned.
         """
-        return self.execute(no_response_expected, pdu_diag.ForceListenOnlyModeRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ForceListenOnlyModeRequest(dev_id=slave))
 
     def diag_clear_counters(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose clear counters (code 0x08 sub 0x0A).
@@ -267,7 +267,7 @@ def diag_clear_counters(self, *, slave: int = 1, no_response_expected: bool = Fa
 
         Clear ll counters and the diagnostic register. Also, counters are cleared upon power-up
         """
-        return self.execute(no_response_expected, pdu_diag.ClearCountersRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ClearCountersRequest(dev_id=slave))
 
     def diag_read_bus_message_count(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose read bus message count (code 0x08 sub 0x0B).
@@ -280,7 +280,7 @@ def diag_read_bus_message_count(self, *, slave: int = 1, no_response_expected: b
         remote device has detected on the communications systems since its last
         restart, clear counters operation, or power-up
         """
-        return self.execute(no_response_expected, pdu_diag.ReturnBusMessageCountRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ReturnBusMessageCountRequest(dev_id=slave))
 
     def diag_read_bus_comm_error_count(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose read Bus Communication Error Count (code 0x08 sub 0x0C).
@@ -293,7 +293,7 @@ def diag_read_bus_comm_error_count(self, *, slave: int = 1, no_response_expected
         by the remote device since its last restart, clear counter operation, or
         power-up
         """
-        return self.execute(no_response_expected, pdu_diag.ReturnBusCommunicationErrorCountRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ReturnBusCommunicationErrorCountRequest(dev_id=slave))
 
     def diag_read_bus_exception_error_count(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose read Bus Exception Error Count (code 0x08 sub 0x0D).
@@ -306,7 +306,7 @@ def diag_read_bus_exception_error_count(self, *, slave: int = 1, no_response_exp
         responses returned by the remote device since its last restart,
         clear counters operation, or power-up
         """
-        return self.execute(no_response_expected, pdu_diag.ReturnBusExceptionErrorCountRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ReturnBusExceptionErrorCountRequest(dev_id=slave))
 
     def diag_read_slave_message_count(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose read Slave Message Count (code 0x08 sub 0x0E).
@@ -319,7 +319,7 @@ def diag_read_slave_message_count(self, *, slave: int = 1, no_response_expected:
         remote device, that the remote device has processed since
         its last restart, clear counters operation, or power-up
         """
-        return self.execute(no_response_expected, pdu_diag.ReturnSlaveMessageCountRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ReturnSlaveMessageCountRequest(dev_id=slave))
 
     def diag_read_slave_no_response_count(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose read Slave No Response Count (code 0x08 sub 0x0F).
@@ -332,7 +332,7 @@ def diag_read_slave_no_response_count(self, *, slave: int = 1, no_response_expec
         remote device, that the remote device has processed since
         its last restart, clear counters operation, or power-up.
         """
-        return self.execute(no_response_expected, pdu_diag.ReturnSlaveNoResponseCountRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ReturnSlaveNoResponseCountRequest(dev_id=slave))
 
     def diag_read_slave_nak_count(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose read Slave NAK Count (code 0x08 sub 0x10).
@@ -346,7 +346,7 @@ def diag_read_slave_nak_count(self, *, slave: int = 1, no_response_expected: boo
         response, since its last restart, clear counters operation, or power-up.
         Exception responses are described and listed in section 7 .
         """
-        return self.execute(no_response_expected, pdu_diag.ReturnSlaveNAKCountRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ReturnSlaveNAKCountRequest(dev_id=slave))
 
     def diag_read_slave_busy_count(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose read Slave Busy Count (code 0x08 sub 0x11).
@@ -359,7 +359,7 @@ def diag_read_slave_busy_count(self, *, slave: int = 1, no_response_expected: bo
         remote device for which it returned a Slave Device Busy exception response,
         since its last restart, clear counters operation, or power-up.
         """
-        return self.execute(no_response_expected, pdu_diag.ReturnSlaveBusyCountRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ReturnSlaveBusyCountRequest(dev_id=slave))
 
     def diag_read_bus_char_overrun_count(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose read Bus Character Overrun Count (code 0x08 sub 0x12).
@@ -374,7 +374,7 @@ def diag_read_bus_char_overrun_count(self, *, slave: int = 1, no_response_expect
         overrun is caused by data characters arriving at the port faster than they
         can be stored, or by the loss of a character due to a hardware malfunction.
         """
-        return self.execute(no_response_expected, pdu_diag.ReturnSlaveBusCharacterOverrunCountRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ReturnSlaveBusCharacterOverrunCountRequest(dev_id=slave))
 
     def diag_read_iop_overrun_count(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose read Iop overrun count (code 0x08 sub 0x13).
@@ -387,7 +387,7 @@ def diag_read_iop_overrun_count(self, *, slave: int = 1, no_response_expected: b
         faster than they can be stored, or by the loss of a character due
         to a hardware malfunction.  This function is specific to the 884.
         """
-        return self.execute(no_response_expected, pdu_diag.ReturnIopOverrunCountRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ReturnIopOverrunCountRequest(dev_id=slave))
 
     def diag_clear_overrun_counter(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose Clear Overrun Counter and Flag (code 0x08 sub 0x14).
@@ -399,7 +399,7 @@ def diag_clear_overrun_counter(self, *, slave: int = 1, no_response_expected: bo
         An error flag should be cleared, but nothing else in the
         specification mentions is, so it is ignored.
         """
-        return self.execute(no_response_expected, pdu_diag.ClearOverrunCountRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.ClearOverrunCountRequest(dev_id=slave))
 
     def diag_getclear_modbus_response(self, *, data: int = 0, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose Get/Clear modbus plus (code 0x08 sub 0x15).
@@ -418,7 +418,7 @@ def diag_getclear_modbus_response(self, *, data: int = 0, slave: int = 1, no_res
         them. Statistics are also cleared on power-up of the slave
         device.
         """
-        return self.execute(no_response_expected, pdu_diag.GetClearModbusPlusRequest(message=data, slave_id=slave))
+        return self.execute(no_response_expected, pdu_diag.GetClearModbusPlusRequest(message=data, dev_id=slave))
 
     def diag_get_comm_event_counter(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose get event counter (code 0x0B).
@@ -440,7 +440,7 @@ def diag_get_comm_event_counter(self, *, slave: int = 1, no_response_expected: b
         The event counter can be reset by means of the Diagnostics function
         Restart Communications or Clear Counters and Diagnostic Register.
         """
-        return self.execute(no_response_expected, pdu_other_msg.GetCommEventCounterRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_other_msg.GetCommEventCounterRequest(dev_id=slave))
 
     def diag_get_comm_event_log(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Diagnose get event counter (code 0x0C).
@@ -467,7 +467,7 @@ def diag_get_comm_event_log(self, *, slave: int = 1, no_response_expected: bool
         chronological order. Byte 0 is the most recent event. Each new byte
         flushes the oldest byte from the field.
         """
-        return self.execute(no_response_expected, pdu_other_msg.GetCommEventLogRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_other_msg.GetCommEventLogRequest(dev_id=slave))
 
     def write_coils(
         self,
@@ -489,7 +489,7 @@ def write_coils(
 
         Coils are addressed as 0-N (Note some device manuals uses 1-N, assuming 1==0).
         """
-        pdu = pdu_bit.WriteMultipleCoilsRequest(address=address, bits=values, slave_id=slave)
+        pdu = pdu_bit.WriteMultipleCoilsRequest(address=address, bits=values, dev_id=slave)
         return self.execute(no_response_expected, pdu)
 
     def write_registers(
@@ -511,7 +511,7 @@ def write_registers(
         This function is used to write a block of contiguous registers
         (1 to approx. 120 registers) in a remote device.
         """
-        return self.execute(no_response_expected, pdu_reg.WriteMultipleRegistersRequest(address=address, registers=values,slave_id=slave))
+        return self.execute(no_response_expected, pdu_reg.WriteMultipleRegistersRequest(address=address, registers=values,dev_id=slave))
 
     def report_slave_id(self, *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Report slave ID (code 0x11).
@@ -523,7 +523,7 @@ def report_slave_id(self, *, slave: int = 1, no_response_expected: bool = False)
         This function is used to read the description of the type, the current status
         and other information specific to a remote device.
         """
-        return self.execute(no_response_expected, pdu_other_msg.ReportSlaveIdRequest(slave_id=slave))
+        return self.execute(no_response_expected, pdu_other_msg.ReportSlaveIdRequest(dev_id=slave))
 
     def read_file_record(self, records: list[pdu_file_msg.FileRecord], *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Read file record (code 0x14).
@@ -553,7 +553,7 @@ def read_file_record(self, records: list[pdu_file_msg.FileRecord], *, slave: int
         in the expected response, must not exceed the allowable length of the
         MODBUS PDU: 235 bytes.
         """
-        return self.execute(no_response_expected, pdu_file_msg.ReadFileRecordRequest(records, slave_id=slave))
+        return self.execute(no_response_expected, pdu_file_msg.ReadFileRecordRequest(records, dev_id=slave))
 
     def write_file_record(self, records: list[pdu_file_msg.FileRecord], *, slave: int = 1, no_response_expected: bool = False) -> T:
         """Write file record (code 0x15).
@@ -568,7 +568,7 @@ def write_file_record(self, records: list[pdu_file_msg.FileRecord], *, slave: in
         and all record lengths are provided in terms of the number of 16
         bit words.
         """
-        return self.execute(no_response_expected, pdu_file_msg.WriteFileRecordRequest(records=records, slave_id=slave))
+        return self.execute(no_response_expected, pdu_file_msg.WriteFileRecordRequest(records=records, dev_id=slave))
 
     def mask_write_register(
         self,
@@ -593,7 +593,7 @@ def mask_write_register(
 
         The function can be used to set or clear individual bits in the register.
         """
-        return self.execute(no_response_expected, pdu_reg.MaskWriteRegisterRequest(address=address, and_mask=and_mask, or_mask=or_mask, slave_id=slave))
+        return self.execute(no_response_expected, pdu_reg.MaskWriteRegisterRequest(address=address, and_mask=and_mask, or_mask=or_mask, dev_id=slave))
 
     def readwrite_registers(
         self,
@@ -629,7 +629,7 @@ def readwrite_registers(
         if address:
             read_address = address
             write_address = address
-        return self.execute(no_response_expected, pdu_reg.ReadWriteMultipleRegistersRequest( read_address=read_address, read_count=read_count, write_address=write_address, write_registers=values,slave_id=slave))
+        return self.execute(no_response_expected, pdu_reg.ReadWriteMultipleRegistersRequest( read_address=read_address, read_count=read_count, write_address=write_address, write_registers=values,dev_id=slave))
 
     def read_fifo_queue(self, *, address: int = 0x0000, slave: int = 1, no_response_expected: bool = False) -> T:
         """Read FIFO queue (code 0x18).
@@ -649,7 +649,7 @@ def read_fifo_queue(self, *, address: int = 0x0000, slave: int = 1, no_response_
         registers.  The function reads the queue contents, but does not clear
         them.
         """
-        return self.execute(no_response_expected, pdu_file_msg.ReadFifoQueueRequest(address, slave_id=slave))
+        return self.execute(no_response_expected, pdu_file_msg.ReadFifoQueueRequest(address, dev_id=slave))
 
     # code 0x2B sub 0x0D: CANopen General Reference Request and Response, NOT IMPLEMENTED
 
@@ -673,7 +673,7 @@ def read_device_information(self, *, read_code: int | None = None,
         composed of a set of addressable data elements. The data elements are
         called objects and an object Id identifies them.
         """
-        return self.execute(no_response_expected, pdu_mei.ReadDeviceInformationRequest(read_code, object_id, slave_id=slave))
+        return self.execute(no_response_expected, pdu_mei.ReadDeviceInformationRequest(read_code, object_id, dev_id=slave))
 
     # ------------------
     # Converter methods
diff --git a/pymodbus/datastore/context.py b/pymodbus/datastore/context.py
index 4282c40e3..3938953b8 100644
--- a/pymodbus/datastore/context.py
+++ b/pymodbus/datastore/context.py
@@ -158,7 +158,7 @@ class ModbusServerContext:
     """This represents a master collection of slave contexts.
 
     If single is set to true, it will be treated as a single
-    context so every slave_id returns the same context. If single
+    context so every device id returns the same context. If single
     is set to false, it will be interpreted as a collection of
     slave contexts.
     """
diff --git a/pymodbus/framer/base.py b/pymodbus/framer/base.py
index 91ae01dda..ddad1a11b 100644
--- a/pymodbus/framer/base.py
+++ b/pymodbus/framer/base.py
@@ -60,7 +60,7 @@ def buildFrame(self, message: ModbusPDU) -> bytes:
         :param message: The populated request/response to send
         """
         data = message.function_code.to_bytes(1,'big') + message.encode()
-        frame = self.encode(data, message.slave_id, message.transaction_id)
+        frame = self.encode(data, message.dev_id, message.transaction_id)
         return frame
 
     def processIncomingFrame(self, data: bytes) -> tuple[int, ModbusPDU | None]:
@@ -96,7 +96,7 @@ def _processIncomingFrame(self, data: bytes) -> tuple[int, ModbusPDU | None]:
             return used_len, None
         if (result := self.decoder.decode(frame_data)) is None:
             raise ModbusIOException("Unable to decode request")
-        result.slave_id = dev_id
+        result.dev_id = dev_id
         result.transaction_id = tid
         Log.debug("Frame advanced, resetting header!!")
         return used_len, result
diff --git a/pymodbus/pdu/bit_message.py b/pymodbus/pdu/bit_message.py
index efef4f81f..a8f0adada 100644
--- a/pymodbus/pdu/bit_message.py
+++ b/pymodbus/pdu/bit_message.py
@@ -39,7 +39,7 @@ async def update_datastore(self, context: ModbusSlaveContext) -> ModbusPDU:
             self.function_code, self.address, self.count
         )
         response_class = (ReadCoilsResponse if self.function_code == 1 else ReadDiscreteInputsResponse)
-        return response_class(slave_id=self.slave_id, transaction_id=self.transaction_id, bits=cast(list[bool], values))
+        return response_class(dev_id=self.dev_id, transaction_id=self.transaction_id, bits=cast(list[bool], values))
 
 
 class ReadDiscreteInputsRequest(ReadCoilsRequest):
@@ -97,7 +97,7 @@ async def update_datastore(self, context: ModbusSlaveContext) -> ModbusPDU:
             return ExceptionResponse(self.function_code, ExceptionResponse.ILLEGAL_ADDRESS)
         await context.async_setValues(self.function_code, self.address, self.bits)
         values = cast(list[bool], await context.async_getValues(self.function_code, self.address, 1))
-        return WriteSingleCoilResponse(address=self.address, bits=values, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return WriteSingleCoilResponse(address=self.address, bits=values, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
     def get_response_pdu_size(self) -> int:
         """Get response pdu size.
@@ -134,7 +134,7 @@ async def update_datastore(self, context: ModbusSlaveContext) -> ModbusPDU:
         await context.async_setValues(
             self.function_code, self.address, self.bits
         )
-        return WriteMultipleCoilsResponse(address=self.address, count=count, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return WriteMultipleCoilsResponse(address=self.address, count=count, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
     def get_response_pdu_size(self) -> int:
         """Get response pdu size.
diff --git a/pymodbus/pdu/diag_message.py b/pymodbus/pdu/diag_message.py
index 3b8301800..674f367cd 100644
--- a/pymodbus/pdu/diag_message.py
+++ b/pymodbus/pdu/diag_message.py
@@ -21,9 +21,9 @@ class DiagnosticBase(ModbusPDU):
     sub_function_code: int = 9999
     rtu_frame_size = 8
 
-    def __init__(self, message: bytes | int | list | tuple | None = 0, slave_id: int = 1, transaction_id: int = 0) -> None:
+    def __init__(self, message: bytes | int | list | tuple | None = 0, dev_id: int = 1, transaction_id: int = 0) -> None:
         """Initialize a diagnostic request."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id)
         self.message: bytes | int | list | tuple | None = message
 
     def encode(self) -> bytes:
@@ -72,7 +72,7 @@ async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
             ReturnQueryDataResponse.sub_function_code: ReturnQueryDataResponse,
             RestartCommunicationsOptionResponse.sub_function_code: RestartCommunicationsOptionResponse,
         }[self.sub_function_code]
-        return response(message=self.message, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return response(message=self.message, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReturnQueryDataRequest(DiagnosticBase):
@@ -107,7 +107,7 @@ class ReturnDiagnosticRegisterRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         register = pack_bitstring(_MCB.getDiagnosticRegister())
-        return ReturnDiagnosticRegisterResponse(message=register, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReturnDiagnosticRegisterResponse(message=register, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReturnDiagnosticRegisterResponse(DiagnosticBase):
@@ -125,7 +125,7 @@ async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         char = (cast(int, self.message) & 0xFF00) >> 8
         _MCB.Delimiter = char
-        return ChangeAsciiInputDelimiterResponse(message=self.message, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ChangeAsciiInputDelimiterResponse(message=self.message, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ChangeAsciiInputDelimiterResponse(DiagnosticBase):
@@ -142,7 +142,7 @@ class ForceListenOnlyModeRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         _MCB.ListenOnly = True
-        return ForceListenOnlyModeResponse(slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ForceListenOnlyModeResponse(dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ForceListenOnlyModeResponse(DiagnosticBase):
@@ -153,9 +153,9 @@ class ForceListenOnlyModeResponse(DiagnosticBase):
 
     sub_function_code = 0x0004
 
-    def __init__(self, slave_id=1, transaction_id=0):
+    def __init__(self, dev_id=1, transaction_id=0):
         """Initialize to block a return response."""
-        DiagnosticBase.__init__(self, slave_id=slave_id, transaction_id=transaction_id)
+        DiagnosticBase.__init__(self, dev_id=dev_id, transaction_id=transaction_id)
         self.message = []
 
 
@@ -167,7 +167,7 @@ class ClearCountersRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         _MCB.reset()
-        return ClearCountersResponse(slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ClearCountersResponse(dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ClearCountersResponse(DiagnosticBase):
@@ -184,7 +184,7 @@ class ReturnBusMessageCountRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         count = _MCB.Counter.BusMessage
-        return ReturnBusMessageCountResponse(message=count, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReturnBusMessageCountResponse(message=count, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReturnBusMessageCountResponse(DiagnosticBase):
@@ -201,7 +201,7 @@ class ReturnBusCommunicationErrorCountRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         count = _MCB.Counter.BusCommunicationError
-        return ReturnBusCommunicationErrorCountResponse(message=count, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReturnBusCommunicationErrorCountResponse(message=count, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReturnBusCommunicationErrorCountResponse(DiagnosticBase):
@@ -218,7 +218,7 @@ class ReturnBusExceptionErrorCountRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         count = _MCB.Counter.BusExceptionError
-        return ReturnBusExceptionErrorCountResponse(message=count, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReturnBusExceptionErrorCountResponse(message=count, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReturnBusExceptionErrorCountResponse(DiagnosticBase):
@@ -235,7 +235,7 @@ class ReturnSlaveMessageCountRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         count = _MCB.Counter.SlaveMessage
-        return ReturnSlaveMessageCountResponse(message=count, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReturnSlaveMessageCountResponse(message=count, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReturnSlaveMessageCountResponse(DiagnosticBase):
@@ -252,7 +252,7 @@ class ReturnSlaveNoResponseCountRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         count = _MCB.Counter.SlaveNoResponse
-        return ReturnSlaveNoResponseCountResponse(message=count, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReturnSlaveNoResponseCountResponse(message=count, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReturnSlaveNoResponseCountResponse(DiagnosticBase):
@@ -269,7 +269,7 @@ class ReturnSlaveNAKCountRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         count = _MCB.Counter.SlaveNAK
-        return ReturnSlaveNAKCountResponse(message=count, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReturnSlaveNAKCountResponse(message=count, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReturnSlaveNAKCountResponse(DiagnosticBase):
@@ -286,7 +286,7 @@ class ReturnSlaveBusyCountRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         count = _MCB.Counter.SLAVE_BUSY
-        return ReturnSlaveBusyCountResponse(message=count, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReturnSlaveBusyCountResponse(message=count, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReturnSlaveBusyCountResponse(DiagnosticBase):
@@ -303,7 +303,7 @@ class ReturnSlaveBusCharacterOverrunCountRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         count = _MCB.Counter.BusCharacterOverrun
-        return ReturnSlaveBusCharacterOverrunCountResponse(message=count, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReturnSlaveBusCharacterOverrunCountResponse(message=count, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReturnSlaveBusCharacterOverrunCountResponse(DiagnosticBase):
@@ -320,7 +320,7 @@ class ReturnIopOverrunCountRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         count = _MCB.Counter.BusCharacterOverrun
-        return ReturnIopOverrunCountResponse(message=count, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReturnIopOverrunCountResponse(message=count, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReturnIopOverrunCountResponse(DiagnosticBase):
@@ -337,7 +337,7 @@ class ClearOverrunCountRequest(DiagnosticBase):
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """update_datastore the diagnostic request on the given device."""
         _MCB.Counter.BusCharacterOverrun = 0x0000
-        return ClearOverrunCountResponse(slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ClearOverrunCountResponse(dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ClearOverrunCountResponse(DiagnosticBase):
@@ -368,7 +368,7 @@ async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         else:
             message = [self.message]
             message += _MCB.Plus.encode()
-        return GetClearModbusPlusResponse(message=message, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return GetClearModbusPlusResponse(message=message, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
     def encode(self):
         """Encode a diagnostic response."""
diff --git a/pymodbus/pdu/file_message.py b/pymodbus/pdu/file_message.py
index 85f1197ac..80297cd84 100644
--- a/pymodbus/pdu/file_message.py
+++ b/pymodbus/pdu/file_message.py
@@ -35,9 +35,9 @@ class ReadFileRecordRequest(ModbusPDU):
     function_code = 0x14
     rtu_byte_count_pos = 2
 
-    def __init__(self, records: list[FileRecord] | None = None,  slave_id: int = 1, transaction_id: int = 0) -> None:
+    def __init__(self, records: list[FileRecord] | None = None,  dev_id: int = 1, transaction_id: int = 0) -> None:
         """Initialize a new instance."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id)
         self.records: list[FileRecord] = records or []
 
     def encode(self) -> bytes:
@@ -78,7 +78,7 @@ async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         for record in self.records:
             record.record_data = b'SERVER DUMMY RECORD.'
             record.record_length = len(record.record_data) // 2
-        return ReadFileRecordResponse(records=self.records,slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReadFileRecordResponse(records=self.records,dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReadFileRecordResponse(ModbusPDU):
@@ -87,9 +87,9 @@ class ReadFileRecordResponse(ModbusPDU):
     function_code = 0x14
     rtu_byte_count_pos = 2
 
-    def __init__(self, records: list[FileRecord] | None = None, slave_id: int = 1, transaction_id: int = 0) -> None:
+    def __init__(self, records: list[FileRecord] | None = None, dev_id: int = 1, transaction_id: int = 0) -> None:
         """Initialize a new instance."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id)
         self.records: list[FileRecord] = records or []
 
     def encode(self) -> bytes:
@@ -125,9 +125,9 @@ class WriteFileRecordRequest(ModbusPDU):
     function_code = 0x15
     rtu_byte_count_pos = 2
 
-    def __init__(self, records: list[FileRecord] | None = None, slave_id: int = 1, transaction_id: int = 0) -> None:
+    def __init__(self, records: list[FileRecord] | None = None, dev_id: int = 1, transaction_id: int = 0) -> None:
         """Initialize a new instance."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id)
         self.records: list[FileRecord] = records or []
 
     def encode(self) -> bytes:
@@ -171,7 +171,7 @@ def get_response_pdu_size(self) -> int:
 
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """Run the write file record request against the context."""
-        return WriteFileRecordResponse(records=self.records, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return WriteFileRecordResponse(records=self.records, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class WriteFileRecordResponse(ModbusPDU):
@@ -180,9 +180,9 @@ class WriteFileRecordResponse(ModbusPDU):
     function_code = 0x15
     rtu_byte_count_pos = 2
 
-    def __init__(self, records: list[FileRecord] | None = None, slave_id: int = 1, transaction_id: int = 0) -> None:
+    def __init__(self, records: list[FileRecord] | None = None, dev_id: int = 1, transaction_id: int = 0) -> None:
         """Initialize a new instance."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id)
         self.records: list[FileRecord] = records or []
 
     def encode(self) -> bytes:
@@ -223,9 +223,9 @@ class ReadFifoQueueRequest(ModbusPDU):
     function_code = 0x18
     rtu_frame_size = 6
 
-    def __init__(self, address: int = 0, slave_id: int = 1, transaction_id: int = 0) -> None:
+    def __init__(self, address: int = 0, dev_id: int = 1, transaction_id: int = 0) -> None:
         """Initialize a new instance."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id)
         self.address = address
         self.validateAddress()
 
@@ -240,7 +240,7 @@ def decode(self, data: bytes) -> None:
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """Run a read exception status request against the store."""
         values = [0, 1, 2, 3] # server dummy response (should be in datastore)
-        return ReadFifoQueueResponse(values=values, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReadFifoQueueResponse(values=values, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReadFifoQueueResponse(ModbusPDU):
@@ -255,9 +255,9 @@ def calculateRtuFrameSize(cls, buffer: bytes) -> int:
         lo_byte = int(buffer[3])
         return (hi_byte << 16) + lo_byte + 6
 
-    def __init__(self, values: list[int] | None = None, slave_id: int = 1, transaction_id:int  = 0) -> None:
+    def __init__(self, values: list[int] | None = None, dev_id: int = 1, transaction_id:int  = 0) -> None:
         """Initialize a new instance."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id)
         self.values = values or []
 
     def encode(self) -> bytes:
diff --git a/pymodbus/pdu/mei_message.py b/pymodbus/pdu/mei_message.py
index c905ce70e..b3b81418f 100644
--- a/pymodbus/pdu/mei_message.py
+++ b/pymodbus/pdu/mei_message.py
@@ -34,9 +34,9 @@ class ReadDeviceInformationRequest(ModbusPDU):
     sub_function_code = 0x0E
     rtu_frame_size = 7
 
-    def __init__(self, read_code: int | None = None, object_id: int = 0, slave_id: int = 1, transaction_id: int = 0) -> None:
+    def __init__(self, read_code: int | None = None, object_id: int = 0, dev_id: int = 1, transaction_id: int = 0) -> None:
         """Initialize a new instance."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id)
         self.read_code = read_code or DeviceInformation.BASIC
         self.object_id = object_id
 
@@ -59,7 +59,7 @@ async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
             return ExceptionResponse(self.function_code, ExceptionResponse.ILLEGAL_VALUE)
 
         information = DeviceInformationFactory.get(_MCB, self.read_code, self.object_id)
-        return ReadDeviceInformationResponse(read_code=self.read_code, information=information, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReadDeviceInformationResponse(read_code=self.read_code, information=information, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReadDeviceInformationResponse(ModbusPDU):
@@ -84,9 +84,9 @@ def calculateRtuFrameSize(cls, buffer: bytes) -> int:
             count -= 1
         return size + 2
 
-    def __init__(self, read_code: int | None = None, information: dict | None = None, slave_id: int = 1, transaction_id: int = 0) -> None:
+    def __init__(self, read_code: int | None = None, information: dict | None = None, dev_id: int = 1, transaction_id: int = 0) -> None:
         """Initialize a new instance."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id)
         self.read_code = read_code or DeviceInformation.BASIC
         self.information = information or {}
         self.number_of_objects = 0
diff --git a/pymodbus/pdu/other_message.py b/pymodbus/pdu/other_message.py
index ec7ed2db5..fac49d41d 100644
--- a/pymodbus/pdu/other_message.py
+++ b/pymodbus/pdu/other_message.py
@@ -28,7 +28,7 @@ def decode(self, _data: bytes) -> None:
     async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
         """Run a read exception status request against the store."""
         status = _MCB.Counter.summary()
-        return ReadExceptionStatusResponse(status=status, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReadExceptionStatusResponse(status=status, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReadExceptionStatusResponse(ModbusPDU):
@@ -65,7 +65,7 @@ def decode(self, _data: bytes) -> None:
     async def update_datastore(self, _context) -> ModbusPDU:
         """Run a read exception status request against the store."""
         count = _MCB.Counter.Event
-        return GetCommEventCounterResponse(count=count, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return GetCommEventCounterResponse(count=count, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class GetCommEventCounterResponse(ModbusPDU):
@@ -105,7 +105,7 @@ async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
             message_count=_MCB.Counter.BusMessage,
             event_count=_MCB.Counter.Event,
             events=_MCB.getEvents(),
-            slave_id=self.slave_id, transaction_id=self.transaction_id)
+            dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class GetCommEventLogResponse(ModbusPDU):
@@ -114,9 +114,9 @@ class GetCommEventLogResponse(ModbusPDU):
     function_code = 0x0C
     rtu_byte_count_pos = 2
 
-    def __init__(self, status: bool = True, message_count: int = 0, event_count: int = 0, events: list[int] | None = None, slave_id: int = 1, transaction_id: int = 0) -> None:
+    def __init__(self, status: bool = True, message_count: int = 0, event_count: int = 0, events: list[int] | None = None, dev_id: int = 1, transaction_id: int = 0) -> None:
         """Initialize a new instance."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id, status=status)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id, status=status)
         self.message_count = message_count
         self.event_count = event_count
         self.events = events or []
@@ -171,7 +171,7 @@ async def update_datastore(self, _context: ModbusSlaveContext) -> ModbusPDU:
 
         identifier = b"-".join(id_data)
         identifier = identifier or b"Pymodbus"
-        return ReportSlaveIdResponse(identifier=identifier, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReportSlaveIdResponse(identifier=identifier, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReportSlaveIdResponse(ModbusPDU):
@@ -180,9 +180,9 @@ class ReportSlaveIdResponse(ModbusPDU):
     function_code = 0x11
     rtu_byte_count_pos = 2
 
-    def __init__(self, identifier: bytes = b"\x00", status: bool = True, slave_id: int = 1, transaction_id: int = 0) -> None:
+    def __init__(self, identifier: bytes = b"\x00", status: bool = True, dev_id: int = 1, transaction_id: int = 0) -> None:
         """Initialize a new instance."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id, status=status)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id, status=status)
         self.identifier = identifier
         self.byte_count = 0
 
diff --git a/pymodbus/pdu/pdu.py b/pymodbus/pdu/pdu.py
index f4c3f5931..792017c02 100644
--- a/pymodbus/pdu/pdu.py
+++ b/pymodbus/pdu/pdu.py
@@ -18,7 +18,7 @@ class ModbusPDU:
     rtu_byte_count_pos: int = 0
 
     def __init__(self,
-            slave_id: int = 0,
+            dev_id: int = 0,
             transaction_id: int = 0,
             address: int = 0,
             count: int = 0,
@@ -27,7 +27,7 @@ def __init__(self,
             status: int = 1,
         ) -> None:
         """Initialize the base data for a modbus request."""
-        self.slave_id: int = slave_id
+        self.dev_id: int = dev_id
         self.transaction_id: int = transaction_id
         self.address: int = address
         self.bits: list[bool] = bits or []
@@ -58,7 +58,7 @@ def __str__(self) -> str:
         """Build a representation of an exception response."""
         return (
             f"{self.__class__.__name__}("
-            f"slave_id={self.slave_id}, "
+            f"dev_id={self.dev_id}, "
             f"transaction_id={self.transaction_id}, "
             f"address={self.address}, "
             f"count={self.count}, "
@@ -116,7 +116,7 @@ def __init__(
             slave: int = 1,
             transaction: int = 0) -> None:
         """Initialize the modbus exception response."""
-        super().__init__(transaction_id=transaction, slave_id=slave)
+        super().__init__(transaction_id=transaction, dev_id=slave)
         self.function_code = function_code | 0x80
         self.exception_code = exception_code
         Log.error(f"Exception response {self.function_code} / {self.exception_code}")
diff --git a/pymodbus/pdu/register_message.py b/pymodbus/pdu/register_message.py
index 2e3e70f05..8cfcdb96e 100644
--- a/pymodbus/pdu/register_message.py
+++ b/pymodbus/pdu/register_message.py
@@ -40,7 +40,7 @@ async def update_datastore(self, context: ModbusSlaveContext) -> ModbusPDU:
             self.function_code, self.address, self.count
         ))
         response_class = (ReadHoldingRegistersResponse if self.function_code == 3 else ReadInputRegistersResponse)
-        return response_class(registers=values, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return response_class(registers=values, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class ReadHoldingRegistersResponse(ModbusPDU):
@@ -88,12 +88,12 @@ def __init__(self,
             read_count: int = 0,
             write_address: int = 0x00,
             write_registers: list[int] | None = None,
-            slave_id: int = 1,
+            dev_id: int = 1,
             transaction_id: int = 0) -> None:
         """Initialize a new request message."""
         if not write_registers:
             write_registers = []
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id)
         self.read_address = read_address
         self.read_count = read_count
         self.write_address = write_address
@@ -151,7 +151,7 @@ async def update_datastore(self, context: ModbusSlaveContext) -> ModbusPDU:
         registers = cast(list[int], await context.async_getValues(
             self.function_code, self.read_address, self.read_count
         ))
-        return ReadWriteMultipleRegistersResponse(registers=registers, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return ReadWriteMultipleRegistersResponse(registers=registers, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
     def get_response_pdu_size(self) -> int:
         """Get response pdu size.
@@ -238,7 +238,7 @@ async def update_datastore(self, context: ModbusSlaveContext) -> ModbusPDU:
         await context.async_setValues(
             self.function_code, self.address, self.registers
           )
-        return WriteMultipleRegistersResponse(address=self.address, count=self.count, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return WriteMultipleRegistersResponse(address=self.address, count=self.count, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
     def get_response_pdu_size(self) -> int:
         """Get response pdu size.
@@ -269,9 +269,9 @@ class MaskWriteRegisterRequest(ModbusPDU):
     function_code = 0x16
     rtu_frame_size = 10
 
-    def __init__(self, address=0x0000, and_mask=0xFFFF, or_mask=0x0000, slave_id=1, transaction_id=0) -> None:
+    def __init__(self, address=0x0000, and_mask=0xFFFF, or_mask=0x0000, dev_id=1, transaction_id=0) -> None:
         """Initialize a new instance."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id, address=address)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id, address=address)
         self.and_mask = and_mask
         self.or_mask = or_mask
 
@@ -296,7 +296,7 @@ async def update_datastore(self, context: ModbusSlaveContext) -> ModbusPDU:
         await context.async_setValues(
             self.function_code, self.address, [values]
         )
-        return MaskWriteRegisterResponse(address=self.address, and_mask=self.and_mask, or_mask=self.or_mask, slave_id=self.slave_id, transaction_id=self.transaction_id)
+        return MaskWriteRegisterResponse(address=self.address, and_mask=self.and_mask, or_mask=self.or_mask, dev_id=self.dev_id, transaction_id=self.transaction_id)
 
 
 class MaskWriteRegisterResponse(ModbusPDU):
@@ -305,9 +305,9 @@ class MaskWriteRegisterResponse(ModbusPDU):
     function_code = 0x16
     rtu_frame_size = 10
 
-    def __init__(self, address=0x0000, and_mask=0xFFFF, or_mask=0x0000, slave_id=1, transaction_id=0) -> None:
+    def __init__(self, address=0x0000, and_mask=0xFFFF, or_mask=0x0000, dev_id=1, transaction_id=0) -> None:
         """Initialize new instance."""
-        super().__init__(transaction_id=transaction_id, slave_id=slave_id, address=address)
+        super().__init__(transaction_id=transaction_id, dev_id=dev_id, address=address)
         self.and_mask = and_mask
         self.or_mask = or_mask
 
diff --git a/pymodbus/server/async_io.py b/pymodbus/server/async_io.py
index 578aca35c..79e52a9b3 100644
--- a/pymodbus/server/async_io.py
+++ b/pymodbus/server/async_io.py
@@ -155,18 +155,18 @@ async def server_async_execute(self, request, *addr):
         """Handle request."""
         broadcast = False
         try:
-            if self.server.broadcast_enable and not request.slave_id:
+            if self.server.broadcast_enable and not request.dev_id:
                 broadcast = True
                 # if broadcasting then execute on all slave contexts,
                 # note response will be ignored
-                for slave_id in self.server.context.slaves():
-                    response = await request.update_datastore(self.server.context[slave_id])
+                for dev_id in self.server.context.slaves():
+                    response = await request.update_datastore(self.server.context[dev_id])
             else:
-                context = self.server.context[request.slave_id]
+                context = self.server.context[request.dev_id]
                 response = await request.update_datastore(context)
 
         except NoSuchSlaveException:
-            Log.error("requested slave does not exist: {}", request.slave_id)
+            Log.error("requested slave does not exist: {}", request.dev_id)
             if self.server.ignore_missing_slaves:
                 return  # the client will simply timeout waiting for a response
             response = ExceptionResponse(0x00, ExceptionResponse.GATEWAY_NO_RESPONSE)
@@ -180,7 +180,7 @@ async def server_async_execute(self, request, *addr):
         # no response when broadcasting
         if not broadcast:
             response.transaction_id = request.transaction_id
-            response.slave_id = request.slave_id
+            response.dev_id = request.dev_id
             self.server_send(response, *addr)
 
     def server_send(self, pdu, addr):
@@ -293,8 +293,8 @@ def __init__(
         :param address: An optional (interface, port) to bind to.
         :param ignore_missing_slaves: True to not send errors on a request
                         to a missing slave
-        :param broadcast_enable: True to treat slave_id 0 as broadcast address,
-                        False to treat 0 as any other slave_id
+        :param broadcast_enable: True to treat dev_id 0 as broadcast address,
+                        False to treat 0 as any other dev_id
         :param trace_packet: Called with bytestream received/to be sent
         :param trace_pdu: Called with PDU received/to be sent
         :param trace_connect: Called when connected/disconnected
@@ -365,8 +365,8 @@ def __init__(  # pylint: disable=too-many-arguments
         :param password: The password for for decrypting the private key file
         :param ignore_missing_slaves: True to not send errors on a request
                         to a missing slave
-        :param broadcast_enable: True to treat slave_id 0 as broadcast address,
-                        False to treat 0 as any other slave_id
+        :param broadcast_enable: True to treat dev_id 0 as broadcast address,
+                        False to treat 0 as any other dev_id
         """
         self.tls_setup = CommParams(
             comm_type=CommType.TLS,
@@ -423,8 +423,8 @@ def __init__(
         :param address: An optional (interface, port) to bind to.
         :param ignore_missing_slaves: True to not send errors on a request
                             to a missing slave
-        :param broadcast_enable: True to treat slave_id 0 as broadcast address,
-                            False to treat 0 as any other slave_id
+        :param broadcast_enable: True to treat dev_id 0 as broadcast address,
+                            False to treat 0 as any other dev_id
         :param trace_packet: Called with bytestream received/to be sent
         :param trace_pdu: Called with PDU received/to be sent
         :param trace_connect: Called when connected/disconnected
@@ -488,8 +488,8 @@ def __init__(
         :param handle_local_echo: (optional) Discard local echo from dongle.
         :param ignore_missing_slaves: True to not send errors on a request
                             to a missing slave
-        :param broadcast_enable: True to treat slave_id 0 as broadcast address,
-                            False to treat 0 as any other slave_id
+        :param broadcast_enable: True to treat dev_id 0 as broadcast address,
+                            False to treat 0 as any other dev_id
         :param reconnect_delay: reconnect delay in seconds
         :param trace_packet: Called with bytestream received/to be sent
         :param trace_pdu: Called with PDU received/to be sent
diff --git a/test/framer/generator.py b/test/framer/generator.py
index 3f32033eb..0c78be765 100755
--- a/test/framer/generator.py
+++ b/test/framer/generator.py
@@ -23,21 +23,21 @@ def set_calls():
             for tid in (0, 3077):
                 print(f"    tid --> {tid}")
                 client = framer(DecodePDU(False))
-                request = ReadHoldingRegistersRequest(address=124, count=2, slave_id=dev_id)
+                request = ReadHoldingRegistersRequest(address=124, count=2, dev_id=dev_id)
                 request.transaction_id = tid
                 result = client.buildFrame(request)
                 print(f"      request --> {result}")
                 print(f"      request --> {result.hex()}")
                 server = framer(DecodePDU(True))
                 response = ReadHoldingRegistersResponse(registers=[141,142])
-                response.slave_id = dev_id
+                response.dev_id = dev_id
                 response.transaction_id = tid
                 result = server.buildFrame(response)
                 print(f"      response --> {result}")
                 print(f"      response --> {result.hex()}")
                 exception = ExceptionResponse(request.function_code, ExceptionResponse.ILLEGAL_ADDRESS)
                 exception.transaction_id = tid
-                exception.slave_id = dev_id
+                exception.dev_id = dev_id
                 result = server.buildFrame(exception)
                 print(f"      exception --> {result}")
                 print(f"      exception --> {result.hex()}")
diff --git a/test/framer/test_framer.py b/test/framer/test_framer.py
index 5838e3d8d..a07ceed03 100644
--- a/test/framer/test_framer.py
+++ b/test/framer/test_framer.py
@@ -428,7 +428,7 @@ def test_processIncomingFrame_roundtrip(self, entry, test_framer, msg, dev_id, t
             used_len, result = test_framer.processIncomingFrame(msg)
         assert used_len == len(msg)
         assert result
-        assert result.slave_id == dev_id
+        assert result.dev_id == dev_id
         assert result.transaction_id == tid
         expected = test_framer.encode(
             result.function_code.to_bytes(1,'big') + result.encode(),
@@ -447,7 +447,7 @@ def test_framer_encode(self, test_framer, msg):
         with mock.patch.object(ModbusPDU, "encode") as mock_encode:
             message = ModbusPDU()
             message.transaction_id = 0x0001
-            message.slave_id = 0xFF
+            message.dev_id = 0xFF
             message.function_code = 0x01
             mock_encode.return_value = b""
 
diff --git a/test/pdu/test_pdu.py b/test/pdu/test_pdu.py
index b4fe0de85..d441fba43 100644
--- a/test/pdu/test_pdu.py
+++ b/test/pdu/test_pdu.py
@@ -169,14 +169,11 @@ def test_pdu_instance_args(self, pdutype, kwargs):
     def test_pdu_instance_extras(self, pdutype, kwargs):
         """Test that all PDU types can be created."""
         tid = 9112
-        slave_id = 63
-        try:
-            pdu = pdutype(transaction=tid, slave=slave_id, **kwargs)
-        except TypeError:
-            pdu = pdutype(transaction_id=tid, slave_id=slave_id, **kwargs)
+        dev_id = 63
+        pdu = pdutype(transaction_id=tid, dev_id=dev_id, **kwargs)
         assert pdu
         assert str(pdu)
-        assert pdu.slave_id == slave_id
+        assert pdu.dev_id == dev_id
         assert pdu.transaction_id == tid
         assert pdu.function_code > 0
 
diff --git a/test/server/test_server_context.py b/test/server/test_server_context.py
index 6c9148011..73e3b6247 100644
--- a/test/server/test_server_context.py
+++ b/test/server/test_server_context.py
@@ -17,8 +17,8 @@ def setup_method(self):
 
     def test_single_context_gets(self):
         """Test getting on a single context."""
-        for slave_id in range(0, 0xFF):
-            assert self.slave == self.context[slave_id]
+        for dev_id in range(0, 0xFF):
+            assert self.slave == self.context[dev_id]
 
     def test_single_context_deletes(self):
         """Test removing on multiple context."""
@@ -70,8 +70,8 @@ def setup_method(self):
 
     def test_multiple_context_gets(self):
         """Test getting on multiple context."""
-        for slave_id in range(0, 10):
-            assert self.slaves[slave_id] == self.context[slave_id]
+        for dev_id in range(0, 10):
+            assert self.slaves[dev_id] == self.context[dev_id]
 
     def test_multiple_context_deletes(self):
         """Test removing on multiple context."""
@@ -81,9 +81,9 @@ def test_multiple_context_deletes(self):
 
     def test_multiple_context_iter(self):
         """Test iterating over multiple context."""
-        for slave_id, slave in self.context:
-            assert slave == self.slaves[slave_id]
-            assert slave_id in self.context
+        for dev_id, slave in self.context:
+            assert slave == self.slaves[dev_id]
+            assert dev_id in self.context
 
     def test_multiple_context_default(self):
         """Test that the multiple context default values work."""
@@ -94,8 +94,8 @@ def test_multiple_context_default(self):
     def test_multiple_context_set(self):
         """Test a setting multiple slave contexts."""
         slaves = {id: ModbusSlaveContext() for id in range(10)}
-        for slave_id, slave in iter(slaves.items()):
-            self.context[slave_id] = slave
-        for slave_id, slave in iter(slaves.items()):
-            actual = self.context[slave_id]
+        for dev_id, slave in iter(slaves.items()):
+            self.context[dev_id] = slave
+        for dev_id, slave in iter(slaves.items()):
+            actual = self.context[dev_id]
             assert slave == actual