diff --git a/lerobot/common/motors/motors_bus.py b/lerobot/common/motors/motors_bus.py
index 26ae3836..24683730 100644
--- a/lerobot/common/motors/motors_bus.py
+++ b/lerobot/common/motors/motors_bus.py
@@ -20,13 +20,17 @@
 # ruff: noqa: N802
 
 import abc
+import json
 import time
-import traceback
 from enum import Enum
+from functools import cached_property
+from pathlib import Path
+from pprint import pformat
 from typing import Protocol
 
-import numpy as np
+import serial
 import tqdm
+from deepdiff import DeepDiff
 
 from lerobot.common.errors import DeviceAlreadyConnectedError, DeviceNotConnectedError
 from lerobot.common.utils.utils import capture_timestamp_utc
@@ -34,8 +38,8 @@ from lerobot.common.utils.utils import capture_timestamp_utc
 MAX_ID_RANGE = 252
 
 
-def get_group_sync_key(data_name: str, motor_names: list[str]) -> str:
-    group_key = f"{data_name}_" + "_".join(motor_names)
+def get_group_sync_key(data_name: str, motor_ids: list[int]) -> str:
+    group_key = f"{data_name}_" + "_".join([str(idx) for idx in motor_ids])
     return group_key
 
 
@@ -98,7 +102,7 @@ class PortHandler(Protocol):
         self.tx_time_per_byte: float
         self.is_using: bool
         self.port_name: str
-        self.ser: object
+        self.ser: serial.Serial
 
     def openPort(self): ...
     def closePort(self): ...
@@ -153,6 +157,46 @@ class PacketHandler(Protocol):
     def syncWriteTxOnly(self, port, start_address, data_length, param, param_length): ...
 
 
+class GroupSyncRead(Protocol):
+    def __init__(self, port, ph, start_address, data_length):
+        self.port: str
+        self.ph: PortHandler
+        self.start_address: int
+        self.data_length: int
+        self.last_result: bool
+        self.is_param_changed: bool
+        self.param: list
+        self.data_dict: dict
+
+    def makeParam(self): ...
+    def addParam(self, id): ...
+    def removeParam(self, id): ...
+    def clearParam(self): ...
+    def txPacket(self): ...
+    def rxPacket(self): ...
+    def txRxPacket(self): ...
+    def isAvailable(self, id, address, data_length): ...
+    def getData(self, id, address, data_length): ...
+
+
+class GroupSyncWrite(Protocol):
+    def __init__(self, port, ph, start_address, data_length):
+        self.port: str
+        self.ph: PortHandler
+        self.start_address: int
+        self.data_length: int
+        self.is_param_changed: bool
+        self.param: list
+        self.data_dict: dict
+
+    def makeParam(self): ...
+    def addParam(self, id, data): ...
+    def removeParam(self, id): ...
+    def changeParam(self, id, data): ...
+    def clearParam(self): ...
+    def txPacket(self): ...
+
+
 class MotorsBus(abc.ABC):
     """The main LeRobot class for implementing motors buses.
 
@@ -163,7 +207,7 @@ class MotorsBus(abc.ABC):
     Note: This class may evolve in the future should we add support for other manufacturers SDKs.
 
     A MotorsBus allows to efficiently read and write to the attached motors.
-    It represents a several motors daisy-chained together and connected through a serial port.
+    It represents several motors daisy-chained together and connected through a serial port.
 
     A MotorsBus subclass instance requires a port (e.g. `FeetechMotorsBus(port="/dev/tty.usbmodem575E0031751"`)).
     To find the port, you can run our utility script:
@@ -198,6 +242,8 @@ class MotorsBus(abc.ABC):
     model_ctrl_table: dict[str, dict]
     model_resolution_table: dict[str, int]
     model_baudrate_table: dict[str, dict]
+    calibration_required: list[str]
+    default_timeout: int
 
     def __init__(
         self,
@@ -206,73 +252,121 @@ class MotorsBus(abc.ABC):
     ):
         self.port = port
         self.motors = motors
-        self.port_handler: PortHandler | None = None
-        self.packet_handler: PacketHandler | None = None
+        self._validate_motors()
 
-        self.group_readers = {}
-        self.group_writers = {}
-        self.logs = {}
+        self.port_handler: PortHandler
+        self.packet_handler: PacketHandler
+        self.reader: GroupSyncRead
+        self.writer: GroupSyncWrite
 
+        self.logs = {}  # TODO(aliberts): use subclass logger
         self.calibration = None
-        self.is_connected: bool = False
+
+        self._id_to_model = dict(self.motors.values())
+        self._id_to_name = {idx: name for name, (idx, _) in self.motors.items()}
 
     def __len__(self):
         return len(self.motors)
 
-    @property
+    def __repr__(self):
+        return (
+            f"{self.__class__.__name__}(\n"
+            f"    Port: '{self.port}',\n"
+            f"    Motors: \n{pformat(self.motors, indent=8)},\n"
+            ")',\n"
+        )
+
+    @cached_property
+    def _has_different_ctrl_tables(self) -> bool:
+        if len(self.motor_models) < 2:
+            return False
+
+        first_table = self.model_ctrl_table[self.motor_models[0]]
+        return any(DeepDiff(first_table, self.model_ctrl_table[model]) for model in self.motor_models[1:])
+
+    def idx_to_model(self, idx: int) -> str:
+        return self._id_to_model[idx]
+
+    def idx_to_name(self, idx: int) -> str:
+        return self._id_to_name[idx]
+
+    @cached_property
     def motor_names(self) -> list[str]:
         return list(self.motors)
 
-    @property
+    @cached_property
     def motor_models(self) -> list[str]:
         return [model for _, model in self.motors.values()]
 
-    @property
-    def motor_indices(self) -> list[int]:
+    @cached_property
+    def motor_ids(self) -> list[int]:
         return [idx for idx, _ in self.motors.values()]
 
-    def connect(self):
+    def _validate_motors(self) -> None:
+        # TODO(aliberts): improve error messages for this (display problematics values)
+        if len(self.motor_ids) != len(set(self.motor_ids)):
+            raise ValueError("Some motors have the same id.")
+
+        if len(self.motor_names) != len(set(self.motor_names)):
+            raise ValueError("Some motors have the same name.")
+
+        if any(model not in self.model_resolution_table for model in self.motor_models):
+            raise ValueError("Some motors models are not available.")
+
+    @property
+    def is_connected(self) -> bool:
+        return self.port_handler.is_open
+
+    def connect(self) -> None:
         if self.is_connected:
             raise DeviceAlreadyConnectedError(
-                f"{self.__name__}({self.port}) is already connected. Do not call `{self.__name__}.connect()` twice."
+                f"{self.__class__.__name__}('{self.port}') is already connected. Do not call `{self.__class__.__name__}.connect()` twice."
             )
 
-        self._set_handlers()
-
         try:
             if not self.port_handler.openPort():
                 raise OSError(f"Failed to open port '{self.port}'.")
-        except Exception:
-            traceback.print_exc()
+        except (FileNotFoundError, OSError, serial.SerialException) as e:
             print(
-                "\nTry running `python lerobot/scripts/find_motors_bus_port.py` to make sure you are using the correct port.\n"
+                f"\nCould not connect on port '{self.port}'. Make sure you are using the correct port."
+                "\nTry running `python lerobot/scripts/find_motors_bus_port.py`\n"
             )
-            raise
+            raise e
 
-        self._set_timeout()
+        self.set_timeout()
 
-        # Allow to read and write
-        self.is_connected = True
+    def set_timeout(self, timeout_ms: int | None = None):
+        timeout_ms = timeout_ms if timeout_ms is not None else self.default_timeout
+        self.port_handler.setPacketTimeoutMillis(timeout_ms)
 
-    @abc.abstractmethod
-    def _set_handlers(self):
-        pass
-
-    @abc.abstractmethod
-    def _set_timeout(self, timeout: int):
-        pass
-
-    def are_motors_configured(self):
+    @property
+    def are_motors_configured(self) -> bool:
         """
         Only check the motor indices and not baudrate, since if the motor baudrates are incorrect, a
         ConnectionError will be raised anyway.
         """
         try:
-            return (self.motor_indices == self.read("ID")).all()
+            # TODO(aliberts): use ping instead
+            return (self.motor_ids == self.read("ID")).all()
         except ConnectionError as e:
             print(e)
             return False
 
+    def ping(self, motor: str | int, num_retry: int | None = None) -> int:
+        idx = self.get_safe_id(motor)
+        for _ in range(num_retry):
+            model_number, comm, _ = self.packet_handler.ping(self.port, idx)
+            if self._is_comm_success(comm):
+                return model_number
+
+        # TODO(aliberts): Should we?
+        return comm
+
+    @abc.abstractmethod
+    def broadcast_ping(self, num_retry: int | None = None):
+        ...
+        # TODO(aliberts): this will replace 'find_motor_indices'
+
     def find_motor_indices(self, possible_ids: list[str] = None, num_retry: int = 2):
         if possible_ids is None:
             possible_ids = range(MAX_ID_RANGE)
@@ -280,7 +374,7 @@ class MotorsBus(abc.ABC):
         indices = []
         for idx in tqdm.tqdm(possible_ids):
             try:
-                present_idx = self.read_with_motor_ids(self.motor_models, [idx], "ID", num_retry=num_retry)[0]
+                present_idx = self.read("ID", idx, num_retry=num_retry)[0]
             except ConnectionError:
                 continue
 
@@ -294,7 +388,7 @@ class MotorsBus(abc.ABC):
 
         return indices
 
-    def set_baudrate(self, baudrate):
+    def set_baudrate(self, baudrate) -> None:
         present_bus_baudrate = self.port_handler.getBaudRate()
         if present_bus_baudrate != baudrate:
             print(f"Setting bus baud rate to {baudrate}. Previously {present_bus_baudrate}.")
@@ -303,94 +397,207 @@ class MotorsBus(abc.ABC):
             if self.port_handler.getBaudRate() != baudrate:
                 raise OSError("Failed to write bus baud rate.")
 
-    def set_calibration(self, calibration_dict: dict[str, list]):
-        self.calibration = calibration_dict
+    def set_calibration(self, calibration_fpath: Path) -> None:
+        with open(calibration_fpath) as f:
+            calibration = json.load(f)
+
+        self.calibration = {int(idx): val for idx, val in calibration.items()}
 
     @abc.abstractmethod
-    def apply_calibration(self):
+    def calibrate_values(self, ids_values: dict[int, int]) -> dict[int, float]:
         pass
 
     @abc.abstractmethod
-    def revert_calibration(self):
+    def uncalibrate_values(self, ids_values: dict[int, float]) -> dict[int, int]:
         pass
 
-    def read(self, data_name, motor_names: str | list[str] | None = None):
+    @abc.abstractmethod
+    def _is_comm_success(self, comm: int) -> bool:
+        pass
+
+    @staticmethod
+    @abc.abstractmethod
+    def split_int_bytes(value: int, n_bytes: int) -> list[int]:
+        """
+        Splits an unsigned integer into a list of bytes in little-endian order.
+
+        This function extracts the individual bytes of an integer based on the
+        specified number of bytes (`n_bytes`). The output is a list of integers,
+        each representing a byte (0-255).
+
+        **Byte order:** The function returns bytes in **little-endian format**,
+        meaning the least significant byte (LSB) comes first.
+
+        Args:
+            value (int): The unsigned integer to be converted into a byte list. Must be within
+                the valid range for the specified `n_bytes`.
+            n_bytes (int): The number of bytes to use for conversion. Supported values:
+                - 1 (for values 0 to 255)
+                - 2 (for values 0 to 65,535)
+                - 4 (for values 0 to 4,294,967,295)
+
+        Raises:
+            ValueError: If `value` is negative or exceeds the maximum allowed for `n_bytes`.
+            NotImplementedError: If `n_bytes` is not 1, 2, or 4.
+
+        Returns:
+            list[int]: A list of integers, each representing a byte in **little-endian order**.
+
+        Examples:
+            >>> split_int_bytes(0x12, 1)
+            [18]
+            >>> split_int_bytes(0x1234, 2)
+            [52, 18]  # 0x1234 → 0x34 0x12 (little-endian)
+            >>> split_int_bytes(0x12345678, 4)
+            [120, 86, 52, 18]  # 0x12345678 → 0x78 0x56 0x34 0x12
+        """
+        pass
+
+    def get_safe_id(self, motor: str | int) -> int:
+        if isinstance(motor, str):
+            return self.motors[motor][0]
+        elif isinstance(motor, int):
+            return motor
+        else:
+            raise ValueError(f"{motor} should be int or str.")
+
+    def read(
+        self, data_name: str, motors: str | int | list[str | int] | None = None, num_retry: int = 1
+    ) -> dict[str, float]:
         if not self.is_connected:
             raise DeviceNotConnectedError(
-                f"{self.__name__}({self.port}) is not connected. You need to run `{self.__name__}.connect()`."
+                f"{self.__class__.__name__}('{self.port}') is not connected. You need to run `{self.__class__.__name__}.connect()`."
             )
 
         start_time = time.perf_counter()
-        if motor_names is None:
-            motor_names = self.motor_names
 
-        if isinstance(motor_names, str):
-            motor_names = [motor_names]
+        if motors is None:
+            motors = self.motor_ids
 
-        values = self._read(data_name, motor_names)
+        if isinstance(motors, (str, int)):
+            motors = [motors]
+
+        motor_ids = [self.get_safe_id(motor) for motor in motors]
+        if self._has_different_ctrl_tables:
+            models = [self.idx_to_model(idx) for idx in motor_ids]
+            assert_same_address(self.model_ctrl_table, models, data_name)
+
+        model = self.idx_to_model(next(iter(motor_ids)))
+        addr, n_bytes = self.model_ctrl_table[model][data_name]
+
+        comm, ids_values = self._read(motor_ids, addr, n_bytes, num_retry)
+        if not self._is_comm_success(comm):
+            raise ConnectionError(
+                f"Failed to read {data_name} on port {self.port} for ids {motor_ids}:"
+                f"{self.packet_handler.getTxRxResult(comm)}"
+            )
+
+        if data_name in self.calibration_required and self.calibration is not None:
+            ids_values = self.calibrate_values(ids_values)
+
+        # TODO(aliberts): return keys in the same format we got them?
+        ids_values = {self.idx_to_name(idx): val for idx, val in ids_values.items()}
 
         # log the number of seconds it took to read the data from the motors
-        delta_ts_name = get_log_name("delta_timestamp_s", "read", data_name, motor_names)
+        delta_ts_name = get_log_name("delta_timestamp_s", "read", data_name, motor_ids)
         self.logs[delta_ts_name] = time.perf_counter() - start_time
 
         # log the utc time at which the data was received
-        ts_utc_name = get_log_name("timestamp_utc", "read", data_name, motor_names)
+        ts_utc_name = get_log_name("timestamp_utc", "read", data_name, motor_ids)
         self.logs[ts_utc_name] = capture_timestamp_utc()
 
-        return values
+        return ids_values
 
-    @abc.abstractmethod
-    def _read(self, data_name: str, motor_names: list[str]):
-        pass
+    def _read(
+        self, motor_ids: list[str], address: int, n_bytes: int, num_retry: int = 1
+    ) -> tuple[int, dict[int, int]]:
+        self.reader.clearParam()
+        self.reader.start_address = address
+        self.reader.data_length = n_bytes
 
-    def write(
-        self, data_name: str, values: int | float | np.ndarray, motor_names: str | list[str] | None = None
-    ) -> None:
+        # FIXME(aliberts, pkooij): We should probably not have to do this.
+        # Let's try to see if we can do with better comm status handling instead.
+        # self.port_handler.ser.reset_output_buffer()
+        # self.port_handler.ser.reset_input_buffer()
+
+        for idx in motor_ids:
+            self.reader.addParam(idx)
+
+        for _ in range(num_retry):
+            comm = self.reader.txRxPacket()
+            if self._is_comm_success(comm):
+                break
+
+        values = {idx: self.reader.getData(idx, address, n_bytes) for idx in motor_ids}
+        return comm, values
+
+    # TODO(aliberts, pkooij): Implementing something like this could get much faster read times.
+    # Note: this could be at the cost of increase latency between the moment the data is produced by the
+    # motors and the moment it is used by a policy
+    # def _async_read(self, motor_ids: list[str], address: int, n_bytes: int):
+    #     self.reader.rxPacket()
+    #     self.reader.txPacket()
+    #     for idx in motor_ids:
+    #         value = self.reader.getData(idx, address, n_bytes)
+
+    def write(self, data_name: str, values_dict: dict[str | int, int], num_retry: int = 1) -> None:
         if not self.is_connected:
             raise DeviceNotConnectedError(
-                f"{self.__name__}({self.port}) is not connected. You need to run `{self.__name__}.connect()`."
+                f"{self.__class__.__name__}('{self.port}') is not connected. You need to run `{self.__class__.__name__}.connect()`."
             )
 
         start_time = time.perf_counter()
 
-        if motor_names is None:
-            motor_names = self.motor_names
+        ids_values = {self.get_safe_id(motor): val for motor, val in values_dict.items()}
 
-        if isinstance(motor_names, str):
-            motor_names = [motor_names]
+        if self._has_different_ctrl_tables:
+            models = [self.idx_to_model(idx) for idx in ids_values]
+            assert_same_address(self.model_ctrl_table, models, data_name)
 
-        if isinstance(values, (int, float, np.integer)):
-            values = [int(values)] * len(motor_names)
+        if data_name in self.calibration_required and self.calibration is not None:
+            ids_values = self.uncalibrate_values(ids_values)
 
-        self._write(data_name, values, motor_names)
+        model = self.idx_to_model(next(iter(ids_values)))
+        addr, n_bytes = self.model_ctrl_table[model][data_name]
+
+        comm = self._write(ids_values, addr, n_bytes, num_retry)
+        if not self._is_comm_success(comm):
+            raise ConnectionError(
+                f"Failed to write {data_name} on port {self.port} for ids {list(ids_values)}:"
+                f"{self.packet_handler.getTxRxResult(comm)}"
+            )
 
         # log the number of seconds it took to write the data to the motors
-        delta_ts_name = get_log_name("delta_timestamp_s", "write", data_name, motor_names)
+        delta_ts_name = get_log_name("delta_timestamp_s", "write", data_name, list(ids_values))
         self.logs[delta_ts_name] = time.perf_counter() - start_time
 
-        # TODO(rcadene): should we log the time before sending the write command?
         # log the utc time when the write has been completed
-        ts_utc_name = get_log_name("timestamp_utc", "write", data_name, motor_names)
+        ts_utc_name = get_log_name("timestamp_utc", "write", data_name, list(ids_values))
         self.logs[ts_utc_name] = capture_timestamp_utc()
 
-    @abc.abstractmethod
-    def _write(self, data_name: str, values: list[int], motor_names: list[str]) -> None:
-        pass
+    def _write(self, ids_values: dict[int, int], address: int, n_bytes: int, num_retry: int = 1) -> int:
+        self.writer.clearParam()
+        self.writer.start_address = address
+        self.writer.data_length = n_bytes
+
+        for idx, value in ids_values.items():
+            data = self.split_int_bytes(value, n_bytes)
+            self.writer.addParam(idx, data)
+
+        for _ in range(num_retry):
+            comm = self.writer.txPacket()
+            if self._is_comm_success(comm):
+                break
+
+        return comm
 
     def disconnect(self) -> None:
         if not self.is_connected:
             raise DeviceNotConnectedError(
-                f"{self.__name__}({self.port}) is not connected. Try running `{self.__name__}.connect()` first."
+                f"{self.__class__.__name__}('{self.port}') is not connected. Try running `{self.__class__.__name__}.connect()` first."
             )
 
-        if self.port_handler is not None:
-            self.port_handler.closePort()
-            self.port_handler = None
-
-        self.packet_handler = None
-        self.group_readers = {}
-        self.group_writers = {}
-        self.is_connected = False
+        self.port_handler.closePort()
 
     def __del__(self):
         if self.is_connected: