diff --git a/examples/eps_read_software_ids.py b/examples/eps_read_software_ids.py
new file mode 100755
index 00000000000000..c285582ff4d0f7
--- /dev/null
+++ b/examples/eps_read_software_ids.py
@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+import sys
+import os
+sys.path.append(os.path.join(os.path.dirname(os.path.realpath(__file__)), ".."))
+from python import Panda
+from python.uds import UdsClient, NegativeResponseError, DATA_IDENTIFIER_TYPE
+
+if __name__ == "__main__":
+  address = 0x18da30f1 # Honda EPS
+  panda = Panda()
+  uds_client = UdsClient(panda, address, debug=False)
+
+  print("tester present ...")
+  uds_client.tester_present()
+
+  try:
+    print("")
+    print("read data by id: boot software id ...")
+    data = uds_client.read_data_by_identifier(DATA_IDENTIFIER_TYPE.BOOT_SOFTWARE_IDENTIFICATION)
+    print(data.decode('utf-8'))
+  except NegativeResponseError as e:
+    print(e)
+
+  try:
+    print("")
+    print("read data by id: application software id ...")
+    data = uds_client.read_data_by_identifier(DATA_IDENTIFIER_TYPE.APPLICATION_SOFTWARE_IDENTIFICATION)
+    print(data.decode('utf-8'))
+  except NegativeResponseError as e:
+    print(e)
+
+  try:
+    print("")
+    print("read data by id: application data id ...")
+    data = uds_client.read_data_by_identifier(DATA_IDENTIFIER_TYPE.APPLICATION_DATA_IDENTIFICATION)
+    print(data.decode('utf-8'))
+  except NegativeResponseError as e:
+    print(e)
+
+  try:
+    print("")
+    print("read data by id: boot software fingerprint ...")
+    data = uds_client.read_data_by_identifier(DATA_IDENTIFIER_TYPE.BOOT_SOFTWARE_FINGERPRINT)
+    print(data.decode('utf-8'))
+  except NegativeResponseError as e:
+    print(e)
+
+  try:
+    print("")
+    print("read data by id: application software fingerprint ...")
+    data = uds_client.read_data_by_identifier(DATA_IDENTIFIER_TYPE.APPLICATION_SOFTWARE_FINGERPRINT)
+    print(data.decode('utf-8'))
+  except NegativeResponseError as e:
+    print(e)
+
+  try:
+    print("")
+    print("read data by id: application data fingerprint ...")
+    data = uds_client.read_data_by_identifier(DATA_IDENTIFIER_TYPE.APPLICATION_DATA_FINGERPRINT)
+    print(data.decode('utf-8'))
+  except NegativeResponseError as e:
+    print(e)
diff --git a/python/uds.py b/python/uds.py
new file mode 100644
index 00000000000000..11ae3d3cfca20f
--- /dev/null
+++ b/python/uds.py
@@ -0,0 +1,767 @@
+#!/usr/bin/env python3
+import time
+import struct
+from typing import NamedTuple, List
+from enum import IntEnum
+from queue import Queue, Empty
+from threading import Thread
+from binascii import hexlify
+
+class SERVICE_TYPE(IntEnum):
+  DIAGNOSTIC_SESSION_CONTROL         = 0x10
+  ECU_RESET                          = 0x11
+  SECURITY_ACCESS                    = 0x27
+  COMMUNICATION_CONTROL              = 0x28
+  TESTER_PRESENT                     = 0x3E
+  ACCESS_TIMING_PARAMETER            = 0x83
+  SECURED_DATA_TRANSMISSION          = 0x84
+  CONTROL_DTC_SETTING                = 0x85
+  RESPONSE_ON_EVENT                  = 0x86
+  LINK_CONTROL                       = 0x87
+  READ_DATA_BY_IDENTIFIER            = 0x22
+  READ_MEMORY_BY_ADDRESS             = 0x23
+  READ_SCALING_DATA_BY_IDENTIFIER    = 0x24
+  READ_DATA_BY_PERIODIC_IDENTIFIER   = 0x2A
+  DYNAMICALLY_DEFINE_DATA_IDENTIFIER = 0x2C
+  WRITE_DATA_BY_IDENTIFIER           = 0x2E
+  WRITE_MEMORY_BY_ADDRESS            = 0x3D
+  CLEAR_DIAGNOSTIC_INFORMATION       = 0x14
+  READ_DTC_INFORMATION               = 0x19
+  INPUT_OUTPUT_CONTROL_BY_IDENTIFIER = 0x2F
+  ROUTINE_CONTROL                    = 0x31
+  REQUEST_DOWNLOAD                   = 0x34
+  REQUEST_UPLOAD                     = 0x35
+  TRANSFER_DATA                      = 0x36
+  REQUEST_TRANSFER_EXIT              = 0x37
+
+class SESSION_TYPE(IntEnum):
+  DEFAULT = 1
+  PROGRAMMING = 2
+  EXTENDED_DIAGNOSTIC = 3
+  SAFETY_SYSTEM_DIAGNOSTIC = 4
+
+class RESET_TYPE(IntEnum):
+  HARD = 1
+  KEY_OFF_ON = 2
+  SOFT = 3
+  ENABLE_RAPID_POWER_SHUTDOWN = 4
+  DISABLE_RAPID_POWER_SHUTDOWN = 5
+
+class ACCESS_TYPE(IntEnum):
+  REQUEST_SEED = 1
+  SEND_KEY = 2
+
+class CONTROL_TYPE(IntEnum):
+  ENABLE_RX_ENABLE_TX = 0
+  ENABLE_RX_DISABLE_TX = 1
+  DISABLE_RX_ENABLE_TX = 2
+  DISABLE_RX_DISABLE_TX = 3
+
+class MESSAGE_TYPE(IntEnum):
+  NORMAL = 1
+  NETWORK_MANAGEMENT = 2
+  NORMAL_AND_NETWORK_MANAGEMENT = 3
+
+class TIMING_PARAMETER_TYPE(IntEnum):
+  READ_EXTENDED_SET = 1
+  SET_TO_DEFAULT_VALUES = 2
+  READ_CURRENTLY_ACTIVE = 3
+  SET_TO_GIVEN_VALUES = 4
+
+class DTC_SETTING_TYPE(IntEnum):
+  ON = 1
+  OFF = 2
+
+class RESPONSE_EVENT_TYPE(IntEnum):
+  STOP_RESPONSE_ON_EVENT = 0
+  ON_DTC_STATUS_CHANGE = 1
+  ON_TIMER_INTERRUPT = 2
+  ON_CHANGE_OF_DATA_IDENTIFIER = 3
+  REPORT_ACTIVATED_EVENTS = 4
+  START_RESPONSE_ON_EVENT = 5
+  CLEAR_RESPONSE_ON_EVENT = 6
+  ON_COMPARISON_OF_VALUES = 7
+
+class LINK_CONTROL_TYPE(IntEnum):
+  VERIFY_BAUDRATE_TRANSITION_WITH_FIXED_BAUDRATE = 1
+  VERIFY_BAUDRATE_TRANSITION_WITH_SPECIFIC_BAUDRATE = 2
+  TRANSITION_BAUDRATE = 3
+
+class BAUD_RATE_TYPE(IntEnum):
+  PC9600 = 1
+  PC19200 = 2
+  PC38400 = 3
+  PC57600 = 4
+  PC115200 = 5
+  CAN125000 = 16
+  CAN250000 = 17
+  CAN500000 = 18
+  CAN1000000 = 19
+
+class DATA_IDENTIFIER_TYPE(IntEnum):
+  BOOT_SOFTWARE_IDENTIFICATION = 0xF180
+  APPLICATION_SOFTWARE_IDENTIFICATION = 0xF181
+  APPLICATION_DATA_IDENTIFICATION = 0xF182
+  BOOT_SOFTWARE_FINGERPRINT = 0xF183
+  APPLICATION_SOFTWARE_FINGERPRINT = 0xF184
+  APPLICATION_DATA_FINGERPRINT = 0xF185
+  ACTIVE_DIAGNOSTIC_SESSION = 0xF186
+  VEHICLE_MANUFACTURER_SPARE_PART_NUMBER = 0xF187
+  VEHICLE_MANUFACTURER_ECU_SOFTWARE_NUMBER = 0xF188
+  VEHICLE_MANUFACTURER_ECU_SOFTWARE_VERSION_NUMBER = 0xF189
+  SYSTEM_SUPPLIER_IDENTIFIER = 0xF18A
+  ECU_MANUFACTURING_DATE = 0xF18B
+  ECU_SERIAL_NUMBER = 0xF18C
+  SUPPORTED_FUNCTIONAL_UNITS = 0xF18D
+  VEHICLE_MANUFACTURER_KIT_ASSEMBLY_PART_NUMBER = 0xF18E
+  VIN = 0xF190
+  VEHICLE_MANUFACTURER_ECU_HARDWARE_NUMBER = 0xF191
+  SYSTEM_SUPPLIER_ECU_HARDWARE_NUMBER = 0xF192
+  SYSTEM_SUPPLIER_ECU_HARDWARE_VERSION_NUMBER = 0xF193
+  SYSTEM_SUPPLIER_ECU_SOFTWARE_NUMBER = 0xF194
+  SYSTEM_SUPPLIER_ECU_SOFTWARE_VERSION_NUMBER = 0xF195
+  EXHAUST_REGULATION_OR_TYPE_APPROVAL_NUMBER = 0xF196
+  SYSTEM_NAME_OR_ENGINE_TYPE = 0xF197
+  REPAIR_SHOP_CODE_OR_TESTER_SERIAL_NUMBER = 0xF198
+  PROGRAMMING_DATE = 0xF199
+  CALIBRATION_REPAIR_SHOP_CODE_OR_CALIBRATION_EQUIPMENT_SERIAL_NUMBER = 0xF19A
+  CALIBRATION_DATE = 0xF19B
+  CALIBRATION_EQUIPMENT_SOFTWARE_NUMBER = 0xF19C
+  ECU_INSTALLATION_DATE = 0xF19D
+  ODX_FILE = 0xF19E
+  ENTITY = 0xF19F
+
+class TRANSMISSION_MODE_TYPE(IntEnum):
+  SEND_AT_SLOW_RATE = 1
+  SEND_AT_MEDIUM_RATE = 2
+  SEND_AT_FAST_RATE = 3
+  STOP_SENDING = 4
+
+class DYNAMIC_DEFINITION_TYPE(IntEnum):
+  DEFINE_BY_IDENTIFIER = 1
+  DEFINE_BY_MEMORY_ADDRESS = 2
+  CLEAR_DYNAMICALLY_DEFINED_DATA_IDENTIFIER = 3
+
+class DynamicSourceDefinition(NamedTuple):
+  data_identifier: int
+  position: int
+  memory_size: int
+  memory_address: int
+
+class DTC_GROUP_TYPE(IntEnum):
+  EMISSIONS = 0x000000
+  ALL = 0xFFFFFF
+
+class DTC_REPORT_TYPE(IntEnum):
+  NUMBER_OF_DTC_BY_STATUS_MASK = 0x01
+  DTC_BY_STATUS_MASK = 0x02
+  DTC_SNAPSHOT_IDENTIFICATION = 0x03
+  DTC_SNAPSHOT_RECORD_BY_DTC_NUMBER = 0x04
+  DTC_SNAPSHOT_RECORD_BY_RECORD_NUMBER = 0x05
+  DTC_EXTENDED_DATA_RECORD_BY_DTC_NUMBER = 0x06
+  NUMBER_OF_DTC_BY_SEVERITY_MASK_RECORD = 0x07
+  DTC_BY_SEVERITY_MASK_RECORD = 0x08
+  SEVERITY_INFORMATION_OF_DTC = 0x09
+  SUPPORTED_DTC = 0x0A
+  FIRST_TEST_FAILED_DTC = 0x0B
+  FIRST_CONFIRMED_DTC = 0x0C
+  MOST_RECENT_TEST_FAILED_DTC = 0x0D
+  MOST_RECENT_CONFIRMED_DTC = 0x0E
+  MIRROR_MEMORY_DTC_BY_STATUS_MASK = 0x0F
+  MIRROR_MEMORY_DTC_EXTENDED_DATA_RECORD_BY_DTC_NUMBER = 0x10
+  NUMBER_OF_MIRROR_MEMORY_DTC_BY_STATUS_MASK = 0x11
+  NUMBER_OF_EMISSIONS_RELATED_OBD_DTC_BY_STATUS_MASK = 0x12
+  EMISSIONS_RELATED_OBD_DTC_BY_STATUS_MASK = 0x13
+  DTC_FAULT_DETECTION_COUNTER = 0x14
+  DTC_WITH_PERMANENT_STATUS = 0x15
+
+class DTC_STATUS_MASK_TYPE(IntEnum):
+  TEST_FAILED = 0x01
+  TEST_FAILED_THIS_OPERATION_CYCLE = 0x02
+  PENDING_DTC = 0x04
+  CONFIRMED_DTC = 0x08
+  TEST_NOT_COMPLETED_SINCE_LAST_CLEAR = 0x10
+  TEST_FAILED_SINCE_LAST_CLEAR = 0x20
+  TEST_NOT_COMPLETED_THIS_OPERATION_CYCLE = 0x40
+  WARNING_INDICATOR_REQUESTED = 0x80
+  ALL = 0xFF
+
+class DTC_SEVERITY_MASK_TYPE(IntEnum):
+  MAINTENANCE_ONLY = 0x20
+  CHECK_AT_NEXT_HALT = 0x40
+  CHECK_IMMEDIATELY = 0x80
+  ALL = 0xE0
+
+class CONTROL_PARAMETER_TYPE(IntEnum):
+  RETURN_CONTROL_TO_ECU = 0
+  RESET_TO_DEFAULT = 1
+  FREEZE_CURRENT_STATE = 2
+  SHORT_TERM_ADJUSTMENT = 3
+
+class ROUTINE_CONTROL_TYPE(IntEnum):
+  START = 1
+  STOP = 2
+  REQUEST_RESULTS = 3
+
+class ROUTINE_IDENTIFIER_TYPE(IntEnum):
+  ERASE_MEMORY = 0xFF00
+  CHECK_PROGRAMMING_DEPENDENCIES = 0xFF01
+  ERASE_MIRROR_MEMORY_DTCS = 0xFF02
+
+class MessageTimeoutError(Exception):
+  pass
+
+class NegativeResponseError(Exception):
+  def __init__(self, message, service_id, error_code):
+    super(Exception, self).__init__(message)
+    self.service_id = service_id
+    self.error_code = error_code
+
+class InvalidServiceIdError(Exception):
+  pass
+
+class InvalidSubFunctioneError(Exception):
+  pass
+
+_negative_response_codes = {
+    0x00: 'positive response',
+    0x10: 'general reject',
+    0x11: 'service not supported',
+    0x12: 'sub-function not supported',
+    0x13: 'incorrect message length or invalid format',
+    0x14: 'response too long',
+    0x21: 'busy repeat request',
+    0x22: 'conditions not correct',
+    0x24: 'request sequence error',
+    0x25: 'no response from subnet component',
+    0x26: 'failure prevents execution of requested action',
+    0x31: 'request out of range',
+    0x33: 'security access denied',
+    0x35: 'invalid key',
+    0x36: 'exceed numebr of attempts',
+    0x37: 'required time delay not expired',
+    0x70: 'upload download not accepted',
+    0x71: 'transfer data suspended',
+    0x72: 'general programming failure',
+    0x73: 'wrong block sequence counter',
+    0x78: 'request correctly received - response pending',
+    0x7e: 'sub-function not supported in active session',
+    0x7f: 'service not supported in active session',
+    0x81: 'rpm too high',
+    0x82: 'rpm too low',
+    0x83: 'engine is running',
+    0x84: 'engine is not running',
+    0x85: 'engine run time too low',
+    0x86: 'temperature too high',
+    0x87: 'temperature too low',
+    0x88: 'vehicle speed too high',
+    0x89: 'vehicle speed too low',
+    0x8a: 'throttle/pedal too high',
+    0x8b: 'throttle/pedal too low',
+    0x8c: 'transmission not in neutral',
+    0x8d: 'transmission not in gear',
+    0x8f: 'brake switch(es) not closed',
+    0x90: 'shifter lever not in park',
+    0x91: 'torque converter clutch locked',
+    0x92: 'voltage too high',
+    0x93: 'voltage too low',
+}
+
+class IsoTpMessage():
+  def __init__(self, can_tx_queue: Queue, can_rx_queue: Queue, timeout: float, debug: bool=False):
+    self.can_tx_queue = can_tx_queue
+    self.can_rx_queue = can_rx_queue
+    self.timeout = timeout
+    self.debug = debug
+
+  def send(self, dat: bytes) -> None:
+    self.tx_dat = dat
+    self.tx_len = len(dat)
+    self.tx_idx = 0
+    self.tx_done = False
+
+    if self.debug: print(f"ISO-TP: REQUEST - {hexlify(self.tx_dat)}")
+    self._tx_first_frame()
+
+  def _tx_first_frame(self) -> None:
+    if self.tx_len < 8:
+      # single frame (send all bytes)
+      if self.debug: print("ISO-TP: TX - single frame")
+      msg = (bytes([self.tx_len]) + self.tx_dat).ljust(8, b"\x00")
+      self.tx_done = True
+    else:
+      # first frame (send first 6 bytes)
+      if self.debug: print("ISO-TP: TX - first frame")
+      msg = (struct.pack("!H", 0x1000 | self.tx_len) + self.tx_dat[:6]).ljust(8, b"\x00")
+    self.can_tx_queue.put(msg)
+
+  def recv(self) -> bytes:
+    self.rx_dat = b""
+    self.rx_len = 0
+    self.rx_idx = 0
+    self.rx_done = False
+
+    try:
+      while True:
+        self._isotp_rx_next()
+        if self.tx_done and self.rx_done:
+          return self.rx_dat
+    except Empty:
+      raise MessageTimeoutError("timeout waiting for response")
+    finally:
+      if self.debug: print(f"ISO-TP: RESPONSE - {hexlify(self.rx_dat)}")
+
+  def _isotp_rx_next(self) -> None:
+    rx_data = self.can_rx_queue.get(block=True, timeout=self.timeout)
+
+    # single rx_frame
+    if rx_data[0] >> 4 == 0x0:
+      self.rx_len = rx_data[0] & 0xFF
+      self.rx_dat = rx_data[1:1+self.rx_len]
+      self.rx_idx = 0
+      self.rx_done = True
+      if self.debug: print(f"ISO-TP: RX - single frame - idx={self.rx_idx} done={self.rx_done}")
+      return
+
+    # first rx_frame
+    if rx_data[0] >> 4 == 0x1:
+      self.rx_len = ((rx_data[0] & 0x0F) << 8) + rx_data[1]
+      self.rx_dat = rx_data[2:]
+      self.rx_idx = 0
+      self.rx_done = False
+      if self.debug: print(f"ISO-TP: RX - first frame - idx={self.rx_idx} done={self.rx_done}")
+      if self.debug: print(f"ISO-TP: TX - flow control continue")
+      # send flow control message (send all bytes)
+      msg = b"\x30\x00\x00".ljust(8, b"\x00")
+      self.can_tx_queue.put(msg)
+      return
+    
+    # consecutive rx frame
+    if rx_data[0] >> 4 == 0x2:
+      assert self.rx_done == False, "isotp - rx: consecutive frame with no active frame"
+      self.rx_idx += 1
+      assert self.rx_idx & 0xF == rx_data[0] & 0xF, "isotp - rx: invalid consecutive frame index"
+      rx_size = self.rx_len - len(self.rx_dat)
+      self.rx_dat += rx_data[1:1+min(rx_size, 7)]
+      if self.rx_len == len(self.rx_dat):
+        self.rx_done = True
+      if self.debug: print(f"ISO-TP: RX - consecutive frame - idx={self.rx_idx} done={self.rx_done}")
+      return
+
+    # flow control
+    if rx_data[0] >> 4 == 0x3:
+      assert self.tx_done == False, "isotp - rx: flow control with no active frame"
+      assert rx_data[0] != 0x32, "isotp - rx: flow-control overflow/abort"
+      assert rx_data[0] == 0x30 or rx_data[0] == 0x31, "isotp - rx: flow-control transfer state indicator invalid"
+      if rx_data[0] == 0x30:
+        if self.debug: print("ISO-TP: RX - flow control continue")
+        delay_ts = rx_data[2] & 0x7F
+        # scale is 1 milliseconds if first bit == 0, 100 micro seconds if first bit == 1
+        delay_div = 1000. if rx_data[2] & 0x80 == 0 else 10000.
+        # first frame = 6 bytes, each consecutive frame = 7 bytes
+        start = 6 + self.tx_idx * 7
+        count = rx_data[1]
+        end = start + count * 7 if count > 0 else self.tx_len
+        for i in range(start, end, 7):
+          if delay_ts > 0 and i > start:
+            delay_s = delay_ts / delay_div
+            if self.debug: print(f"ISO-TP: TX - delay - seconds={delay_s}")
+            time.sleep(delay_s)
+          self.tx_idx += 1
+          # consecutive tx frames
+          msg = (bytes([0x20 | (self.tx_idx & 0xF)]) + self.tx_dat[i:i+7]).ljust(8, b"\x00")
+          self.can_tx_queue.put(msg)
+        if end >= self.tx_len:
+          self.tx_done = True
+        if self.debug: print(f"ISO-TP: TX - consecutive frame - idx={self.tx_idx} done={self.tx_done}")
+      elif rx_data[0] == 0x31:
+        # wait (do nothing until next flow control message)
+        if self.debug: print("ISO-TP: TX - flow control wait")
+
+class UdsClient():
+  def __init__(self, panda, tx_addr: int, rx_addr: int=None, bus: int=0, timeout: float=10, debug: bool=False):
+    self.panda = panda
+    self.bus = bus
+    self.tx_addr = tx_addr
+    if rx_addr == None:
+      if tx_addr < 0xFFF8:
+        # standard 11 bit response addr (add 8)
+        self.rx_addr = tx_addr+8
+      elif tx_addr > 0x10000000 and tx_addr < 0xFFFFFFFF:
+        # standard 29 bit response addr (flip last two bytes)
+        self.rx_addr = (tx_addr & 0xFFFF0000) + (tx_addr<<8 & 0xFF00) + (tx_addr>>8 & 0xFF)
+      else:
+        raise ValueError("invalid tx_addr: {}".format(tx_addr))
+
+    self.can_tx_queue = Queue()
+    self.can_rx_queue = Queue()
+    self.timeout = timeout
+    self.debug = debug
+
+    self.can_thread = Thread(target=self._can_thread, args=(self.debug,))
+    self.can_thread.daemon = True
+    self.can_thread.start()
+
+  def _can_thread(self, debug: bool=False):
+    try:
+      # allow all output
+      self.panda.set_safety_mode(0x1337)
+      # clear tx buffer
+      self.panda.can_clear(self.bus)
+      # clear rx buffer
+      self.panda.can_clear(0xFFFF)
+
+      while True:
+        # send
+        while not self.can_tx_queue.empty():
+          msg = self.can_tx_queue.get(block=False)
+          if debug: print("CAN-TX: {} - {}".format(hex(self.tx_addr), hexlify(msg)))
+          self.panda.can_send(self.tx_addr, msg, self.bus)
+
+        # receive
+        msgs = self.panda.can_recv()
+        for rx_addr, rx_ts, rx_data, rx_bus in msgs:
+          if rx_bus != self.bus or rx_addr != self.rx_addr or len(rx_data) == 0:
+            continue
+          if debug: print("CAN-RX: {} - {}".format(hex(self.rx_addr), hexlify(rx_data)))
+          self.can_rx_queue.put(rx_data)
+        else:
+          time.sleep(0.01)
+    finally:
+      self.panda.close()
+
+  # generic uds request
+  def _uds_request(self, service_type: SERVICE_TYPE, subfunction: int=None, data: bytes=None) -> bytes:
+    req = bytes([service_type])
+    if subfunction is not None:
+      req += bytes([subfunction])
+    if data is not None:
+      req += data
+
+    # send request, wait for response
+    isotp_msg = IsoTpMessage(self.can_tx_queue, self.can_rx_queue, self.timeout, self.debug)
+    isotp_msg.send(req)
+    while True:
+      resp = isotp_msg.recv()
+      resp_sid = resp[0] if len(resp) > 0 else None
+
+      # negative response
+      if resp_sid == 0x7F:
+        service_id = resp[1] if len(resp) > 1 else -1
+        try:
+          service_desc = SERVICE_TYPE(service_id).name
+        except Exception:
+          service_desc = 'NON_STANDARD_SERVICE'
+        error_code = resp[2] if len(resp) > 2 else -1
+        try:
+          error_desc = _negative_response_codes[error_code]
+        except Exception:
+          error_desc = resp[3:]
+        # wait for another message if response pending
+        if error_code == 0x78:
+          if self.debug: print("UDS-RX: response pending")
+          continue
+        raise NegativeResponseError('{} - {}'.format(service_desc, error_desc), service_id, error_code)
+
+      # positive response
+      if service_type+0x40 != resp_sid:
+        resp_sid_hex = hex(resp_sid) if resp_sid is not None else None
+        raise InvalidServiceIdError('invalid response service id: {}'.format(resp_sid_hex))
+
+      if subfunction is not None:
+        resp_sfn = resp[1] if len(resp) > 1 else None
+        if subfunction != resp_sfn:
+          resp_sfn_hex = hex(resp_sfn) if resp_sfn is not None else None
+          raise InvalidSubFunctioneError('invalid response subfunction: {}'.format(hex(resp_sfn)))
+
+      # return data (exclude service id and sub-function id)
+      return resp[(1 if subfunction is None else 2):]
+
+  # services
+  def diagnostic_session_control(self, session_type: SESSION_TYPE):
+    self._uds_request(SERVICE_TYPE.DIAGNOSTIC_SESSION_CONTROL, subfunction=session_type)
+
+  def ecu_reset(self, reset_type: RESET_TYPE):
+    resp = self._uds_request(SERVICE_TYPE.ECU_RESET, subfunction=reset_type)
+    power_down_time = None
+    if reset_type == RESET_TYPE.ENABLE_RAPID_POWER_SHUTDOWN:
+      power_down_time = resp[0]
+      return power_down_time
+
+  def security_access(self, access_type: ACCESS_TYPE, security_key: bytes=None):
+    request_seed = access_type % 2 != 0
+    if request_seed and security_key is not None:
+      raise ValueError('security_key not allowed')
+    if not request_seed and security_key is None:
+      raise ValueError('security_key is missing')
+    resp = self._uds_request(SERVICE_TYPE.SECURITY_ACCESS, subfunction=access_type, data=security_key)
+    if request_seed:
+      security_seed = resp
+      return security_seed
+
+  def communication_control(self, control_type: CONTROL_TYPE, message_type: MESSAGE_TYPE):
+    data = bytes([message_type])
+    self._uds_request(SERVICE_TYPE.COMMUNICATION_CONTROL, subfunction=control_type, data=data)
+
+  def tester_present(self, ):
+    self._uds_request(SERVICE_TYPE.TESTER_PRESENT, subfunction=0x00)
+
+  def access_timing_parameter(self, timing_parameter_type: TIMING_PARAMETER_TYPE, parameter_values: bytes=None):
+    write_custom_values = timing_parameter_type == TIMING_PARAMETER_TYPE.SET_TO_GIVEN_VALUES
+    read_values = (
+      timing_parameter_type == TIMING_PARAMETER_TYPE.READ_CURRENTLY_ACTIVE or
+      timing_parameter_type == TIMING_PARAMETER_TYPE.READ_EXTENDED_SET
+    )
+    if not write_custom_values and parameter_values is not None:
+      raise ValueError('parameter_values not allowed')
+    if write_custom_values and parameter_values is None:
+      raise ValueError('parameter_values is missing')
+    resp = self._uds_request(SERVICE_TYPE.ACCESS_TIMING_PARAMETER, subfunction=timing_parameter_type, data=parameter_values)
+    if read_values:
+      # TODO: parse response into values?
+      parameter_values = resp
+      return parameter_values
+
+  def secured_data_transmission(self, data: bytes):
+    # TODO: split data into multiple input parameters?
+    resp = self._uds_request(SERVICE_TYPE.SECURED_DATA_TRANSMISSION, subfunction=None, data=data)
+    # TODO: parse response into multiple output values?
+    return resp
+
+  def control_dtc_setting(self, dtc_setting_type: DTC_SETTING_TYPE):
+    self._uds_request(SERVICE_TYPE.CONTROL_DTC_SETTING, subfunction=dtc_setting_type)
+
+  def response_on_event(self, response_event_type: RESPONSE_EVENT_TYPE, store_event: bool, window_time: int, event_type_record: int, service_response_record: int):
+    if store_event:
+      response_event_type |= 0x20
+    # TODO: split record parameters into arrays
+    data = bytes([window_time, event_type_record, service_response_record])
+    resp = self._uds_request(SERVICE_TYPE.RESPONSE_ON_EVENT, subfunction=response_event_type, data=data)
+
+    if response_event_type == RESPONSE_EVENT_TYPE.REPORT_ACTIVATED_EVENTS:
+      return {
+        "num_of_activated_events": resp[0],
+        "data": resp[1:], # TODO: parse the reset of response
+      }
+
+    return {
+      "num_of_identified_events": resp[0],
+      "event_window_time": resp[1],
+      "data": resp[2:], # TODO: parse the reset of response
+    }
+
+  def link_control(self, link_control_type: LINK_CONTROL_TYPE, baud_rate_type: BAUD_RATE_TYPE=None):
+    if link_control_type == LINK_CONTROL_TYPE.VERIFY_BAUDRATE_TRANSITION_WITH_FIXED_BAUDRATE:
+      # baud_rate_type = BAUD_RATE_TYPE
+      data = bytes([baud_rate_type])
+    elif link_control_type == LINK_CONTROL_TYPE.VERIFY_BAUDRATE_TRANSITION_WITH_SPECIFIC_BAUDRATE:
+      # baud_rate_type = custom value (3 bytes big-endian)
+      data = struct.pack('!I', baud_rate_type)[1:]
+    else:
+      data = None
+    self._uds_request(SERVICE_TYPE.LINK_CONTROL, subfunction=link_control_type, data=data)
+
+  def read_data_by_identifier(self, data_identifier_type: DATA_IDENTIFIER_TYPE):
+    # TODO: support list of identifiers
+    data = struct.pack('!H', data_identifier_type)
+    resp = self._uds_request(SERVICE_TYPE.READ_DATA_BY_IDENTIFIER, subfunction=None, data=data)
+    resp_id = struct.unpack('!H', resp[0:2])[0] if len(resp) >= 2 else None
+    if resp_id != data_identifier_type:
+      raise ValueError('invalid response data identifier: {}'.format(hex(resp_id)))
+    return resp[2:]
+
+  def read_memory_by_address(self, memory_address: int, memory_size: int, memory_address_bytes: int=4, memory_size_bytes: int=1):
+    if memory_address_bytes < 1 or memory_address_bytes > 4:
+      raise ValueError('invalid memory_address_bytes: {}'.format(memory_address_bytes))
+    if memory_size_bytes < 1 or memory_size_bytes > 4:
+      raise ValueError('invalid memory_size_bytes: {}'.format(memory_size_bytes))
+    data = bytes([memory_size_bytes<<4 | memory_address_bytes])
+
+    if memory_address >= 1<<(memory_address_bytes*8):
+      raise ValueError('invalid memory_address: {}'.format(memory_address))
+    data += struct.pack('!I', memory_address)[4-memory_address_bytes:]
+    if memory_size >= 1<<(memory_size_bytes*8):
+      raise ValueError('invalid memory_size: {}'.format(memory_size))
+    data += struct.pack('!I', memory_size)[4-memory_size_bytes:]
+
+    resp = self._uds_request(SERVICE_TYPE.READ_MEMORY_BY_ADDRESS, subfunction=None, data=data)
+    return resp
+
+  def read_scaling_data_by_identifier(self, data_identifier_type: DATA_IDENTIFIER_TYPE):
+    data = struct.pack('!H', data_identifier_type)
+    resp = self._uds_request(SERVICE_TYPE.READ_SCALING_DATA_BY_IDENTIFIER, subfunction=None, data=data)
+    resp_id = struct.unpack('!H', resp[0:2])[0] if len(resp) >= 2 else None
+    if resp_id != data_identifier_type:
+      raise ValueError('invalid response data identifier: {}'.format(hex(resp_id)))
+    return resp[2:] # TODO: parse the response
+
+  def read_data_by_periodic_identifier(self, transmission_mode_type: TRANSMISSION_MODE_TYPE, periodic_data_identifier: int):
+    # TODO: support list of identifiers
+    data = bytes([transmission_mode_type, periodic_data_identifier])
+    self._uds_request(SERVICE_TYPE.READ_DATA_BY_PERIODIC_IDENTIFIER, subfunction=None, data=data)
+
+  def dynamically_define_data_identifier(self, dynamic_definition_type: DYNAMIC_DEFINITION_TYPE, dynamic_data_identifier: int, source_definitions: List[DynamicSourceDefinition], memory_address_bytes: int=4, memory_size_bytes: int=1):
+    if memory_address_bytes < 1 or memory_address_bytes > 4:
+      raise ValueError('invalid memory_address_bytes: {}'.format(memory_address_bytes))
+    if memory_size_bytes < 1 or memory_size_bytes > 4:
+      raise ValueError('invalid memory_size_bytes: {}'.format(memory_size_bytes))
+
+    data = struct.pack('!H', dynamic_data_identifier)
+    if dynamic_definition_type == DYNAMIC_DEFINITION_TYPE.DEFINE_BY_IDENTIFIER:
+      for s in source_definitions:
+        data += struct.pack('!H', s["data_identifier"]) + bytes([s["position"], s["memory_size"]])
+    elif dynamic_definition_type == DYNAMIC_DEFINITION_TYPE.DEFINE_BY_MEMORY_ADDRESS:
+      data += bytes([memory_size_bytes<<4 | memory_address_bytes])
+      for s in source_definitions:
+        if s["memory_address"] >= 1<<(memory_address_bytes*8):
+          raise ValueError('invalid memory_address: {}'.format(s["memory_address"]))
+        data += struct.pack('!I', memory_address)[4-memory_address_bytes:]
+        if s["memory_size"] >= 1<<(memory_size_bytes*8):
+          raise ValueError('invalid memory_size: {}'.format(s["memory_size"]))
+        data += struct.pack('!I', s["memory_size"])[4-memory_size_bytes:]
+    elif dynamic_definition_type == DYNAMIC_DEFINITION_TYPE.CLEAR_DYNAMICALLY_DEFINED_DATA_IDENTIFIER:
+      pass
+    else:
+      raise ValueError('invalid dynamic identifier type: {}'.format(hex(dynamic_definition_type)))
+    self._uds_request(SERVICE_TYPE.DYNAMICALLY_DEFINE_DATA_IDENTIFIER, subfunction=dynamic_definition_type, data=data)
+
+  def write_data_by_identifier(self, data_identifier_type: DATA_IDENTIFIER_TYPE, data_record: bytes):
+    data = struct.pack('!H', data_identifier_type) + data_record
+    resp = self._uds_request(SERVICE_TYPE.WRITE_DATA_BY_IDENTIFIER, subfunction=None, data=data)
+    resp_id = struct.unpack('!H', resp[0:2])[0] if len(resp) >= 2 else None
+    if resp_id != data_identifier_type:
+      raise ValueError('invalid response data identifier: {}'.format(hex(resp_id)))
+
+  def write_memory_by_address(self, memory_address: int, memory_size: int, data_record: bytes, memory_address_bytes: int=4, memory_size_bytes: int=1):
+    if memory_address_bytes < 1 or memory_address_bytes > 4:
+      raise ValueError('invalid memory_address_bytes: {}'.format(memory_address_bytes))
+    if memory_size_bytes < 1 or memory_size_bytes > 4:
+      raise ValueError('invalid memory_size_bytes: {}'.format(memory_size_bytes))
+    data = bytes([memory_size_bytes<<4 | memory_address_bytes])
+
+    if memory_address >= 1<<(memory_address_bytes*8):
+      raise ValueError('invalid memory_address: {}'.format(memory_address))
+    data += struct.pack('!I', memory_address)[4-memory_address_bytes:]
+    if memory_size >= 1<<(memory_size_bytes*8):
+      raise ValueError('invalid memory_size: {}'.format(memory_size))
+    data += struct.pack('!I', memory_size)[4-memory_size_bytes:]
+
+    data += data_record
+    self._uds_request(SERVICE_TYPE.WRITE_MEMORY_BY_ADDRESS, subfunction=0x00, data=data)
+
+  def clear_diagnostic_information(self, dtc_group_type: DTC_GROUP_TYPE):
+    data = struct.pack('!I', dtc_group_type)[1:] # 3 bytes
+    self._uds_request(SERVICE_TYPE.CLEAR_DIAGNOSTIC_INFORMATION, subfunction=None, data=data)
+
+  def read_dtc_information(self, dtc_report_type: DTC_REPORT_TYPE, dtc_status_mask_type: DTC_STATUS_MASK_TYPE=DTC_STATUS_MASK_TYPE.ALL, dtc_severity_mask_type: DTC_SEVERITY_MASK_TYPE=DTC_SEVERITY_MASK_TYPE.ALL, dtc_mask_record: int=0xFFFFFF, dtc_snapshot_record_num: int=0xFF, dtc_extended_record_num: int=0xFF):
+    data = b''
+    # dtc_status_mask_type
+    if dtc_report_type == DTC_REPORT_TYPE.NUMBER_OF_DTC_BY_STATUS_MASK or \
+      dtc_report_type == DTC_REPORT_TYPE.DTC_BY_STATUS_MASK or \
+      dtc_report_type == DTC_REPORT_TYPE.MIRROR_MEMORY_DTC_BY_STATUS_MASK or \
+      dtc_report_type == DTC_REPORT_TYPE.NUMBER_OF_MIRROR_MEMORY_DTC_BY_STATUS_MASK or \
+      dtc_report_type == DTC_REPORT_TYPE.NUMBER_OF_EMISSIONS_RELATED_OBD_DTC_BY_STATUS_MASK or \
+      dtc_report_type == DTC_REPORT_TYPE.EMISSIONS_RELATED_OBD_DTC_BY_STATUS_MASK:
+      data += bytes([dtc_status_mask_type])
+    # dtc_mask_record
+    if dtc_report_type == DTC_REPORT_TYPE.DTC_SNAPSHOT_IDENTIFICATION or \
+      dtc_report_type == DTC_REPORT_TYPE.DTC_SNAPSHOT_RECORD_BY_DTC_NUMBER or \
+      dtc_report_type == DTC_REPORT_TYPE.DTC_EXTENDED_DATA_RECORD_BY_DTC_NUMBER or \
+      dtc_report_type == DTC_REPORT_TYPE.MIRROR_MEMORY_DTC_EXTENDED_DATA_RECORD_BY_DTC_NUMBER or \
+      dtc_report_type == DTC_REPORT_TYPE.SEVERITY_INFORMATION_OF_DTC:
+      data += struct.pack('!I', dtc_mask_record)[1:] # 3 bytes
+    # dtc_snapshot_record_num
+    if dtc_report_type == DTC_REPORT_TYPE.DTC_SNAPSHOT_IDENTIFICATION or \
+      dtc_report_type == DTC_REPORT_TYPE.DTC_SNAPSHOT_RECORD_BY_DTC_NUMBER or \
+      dtc_report_type == DTC_REPORT_TYPE.DTC_SNAPSHOT_RECORD_BY_RECORD_NUMBER:
+      data += ord(dtc_snapshot_record_num)
+    # dtc_extended_record_num
+    if dtc_report_type == DTC_REPORT_TYPE.DTC_EXTENDED_DATA_RECORD_BY_DTC_NUMBER or \
+      dtc_report_type == DTC_REPORT_TYPE.MIRROR_MEMORY_DTC_EXTENDED_DATA_RECORD_BY_DTC_NUMBER:
+      data += bytes([dtc_extended_record_num])
+    # dtc_severity_mask_type
+    if dtc_report_type == DTC_REPORT_TYPE.NUMBER_OF_DTC_BY_SEVERITY_MASK_RECORD or \
+      dtc_report_type == DTC_REPORT_TYPE.DTC_BY_SEVERITY_MASK_RECORD:
+      data += bytes([dtc_severity_mask_type, dtc_status_mask_type])
+    
+    resp = self._uds_request(SERVICE_TYPE.READ_DTC_INFORMATION, subfunction=dtc_report_type, data=data)
+
+    # TODO: parse response
+    return resp
+
+  def input_output_control_by_identifier(self, data_identifier_type: DATA_IDENTIFIER_TYPE, control_parameter_type: CONTROL_PARAMETER_TYPE, control_option_record: bytes, control_enable_mask_record: bytes=b''):
+    data = struct.pack('!H', data_identifier_type) + bytes([control_parameter_type]) + control_option_record + control_enable_mask_record
+    resp = self._uds_request(SERVICE_TYPE.INPUT_OUTPUT_CONTROL_BY_IDENTIFIER, subfunction=None, data=data)
+    resp_id = struct.unpack('!H', resp[0:2])[0] if len(resp) >= 2 else None
+    if resp_id != data_identifier_type:
+      raise ValueError('invalid response data identifier: {}'.format(hex(resp_id)))
+    return resp[2:]
+
+  def routine_control(self, routine_control_type: ROUTINE_CONTROL_TYPE, routine_identifier_type: ROUTINE_IDENTIFIER_TYPE, routine_option_record: bytes=b''):
+    data = struct.pack('!H', routine_identifier_type) + routine_option_record
+    resp = self._uds_request(SERVICE_TYPE.ROUTINE_CONTROL, subfunction=routine_control_type, data=data)
+    resp_id = struct.unpack('!H', resp[0:2])[0] if len(resp) >= 2 else None
+    if resp_id != routine_identifier_type:
+      raise ValueError('invalid response routine identifier: {}'.format(hex(resp_id)))
+    return resp[2:]
+
+  def request_download(self, memory_address: int, memory_size: int, memory_address_bytes: int=4, memory_size_bytes: int=4, data_format: int=0x00):
+    data = bytes([data_format])
+
+    if memory_address_bytes < 1 or memory_address_bytes > 4:
+      raise ValueError('invalid memory_address_bytes: {}'.format(memory_address_bytes))
+    if memory_size_bytes < 1 or memory_size_bytes > 4:
+      raise ValueError('invalid memory_size_bytes: {}'.format(memory_size_bytes))
+    data += bytes([memory_size_bytes<<4 | memory_address_bytes])
+
+    if memory_address >= 1<<(memory_address_bytes*8):
+      raise ValueError('invalid memory_address: {}'.format(memory_address))
+    data += struct.pack('!I', memory_address)[4-memory_address_bytes:]
+    if memory_size >= 1<<(memory_size_bytes*8):
+      raise ValueError('invalid memory_size: {}'.format(memory_size))
+    data += struct.pack('!I', memory_size)[4-memory_size_bytes:]
+
+    resp = self._uds_request(SERVICE_TYPE.REQUEST_DOWNLOAD, subfunction=None, data=data)
+    max_num_bytes_len = resp[0] >> 4 if len(resp) > 0 else None
+    if max_num_bytes_len >= 1 and max_num_bytes_len <= 4:
+      max_num_bytes = struct.unpack('!I', (b"\x00"*(4-max_num_bytes_len))+resp[1:max_num_bytes_len+1])[0]
+    else:
+      raise ValueError('invalid max_num_bytes_len: {}'.format(max_num_bytes_len))
+
+    return max_num_bytes # max number of bytes per transfer data request
+
+  def request_upload(self, memory_address: int, memory_size: int, memory_address_bytes: int=4, memory_size_bytes: int=4, data_format: int=0x00):
+    data = bytes([data_format])
+
+    if memory_address_bytes < 1 or memory_address_bytes > 4:
+      raise ValueError('invalid memory_address_bytes: {}'.format(memory_address_bytes))
+    if memory_size_bytes < 1 or memory_size_bytes > 4:
+      raise ValueError('invalid memory_size_bytes: {}'.format(memory_size_bytes))
+    data += bytes([memory_size_bytes<<4 | memory_address_bytes])
+
+    if memory_address >= 1<<(memory_address_bytes*8):
+      raise ValueError('invalid memory_address: {}'.format(memory_address))
+    data += struct.pack('!I', memory_address)[4-memory_address_bytes:]
+    if memory_size >= 1<<(memory_size_bytes*8):
+      raise ValueError('invalid memory_size: {}'.format(memory_size))
+    data += struct.pack('!I', memory_size)[4-memory_size_bytes:]
+
+    resp = self._uds_request(SERVICE_TYPE.REQUEST_UPLOAD, subfunction=None, data=data)
+    max_num_bytes_len = resp[0] >> 4 if len(resp) > 0 else None
+    if max_num_bytes_len >= 1 and max_num_bytes_len <= 4:
+      max_num_bytes = struct.unpack('!I', (b"\x00"*(4-max_num_bytes_len))+resp[1:max_num_bytes_len+1])[0]
+    else:
+      raise ValueError('invalid max_num_bytes_len: {}'.format(max_num_bytes_len))
+
+    return max_num_bytes # max number of bytes per transfer data request
+
+  def transfer_data(self, block_sequence_count: int, data: bytes=b''):
+    data = bytes([block_sequence_count]) + data
+    resp = self._uds_request(SERVICE_TYPE.TRANSFER_DATA, subfunction=None, data=data)
+    resp_id = resp[0] if len(resp) > 0 else None
+    if resp_id != block_sequence_count:
+      raise ValueError('invalid block_sequence_count: {}'.format(resp_id))
+    return resp[1:]
+
+  def request_transfer_exit(self):
+    self._uds_request(SERVICE_TYPE.REQUEST_TRANSFER_EXIT, subfunction=None)