diff --git a/doc/scapy/advanced_usage.rst b/doc/scapy/advanced_usage.rst
index 56f957e7357..dbb4ddf835e 100644
--- a/doc/scapy/advanced_usage.rst
+++ b/doc/scapy/advanced_usage.rst
@@ -1570,6 +1570,53 @@ Close the sockets::
    socket0.close()
    socket1.close()
 
+CAN Calibration Protocol (CCP)
+------------------------------
+
+CCP is derived from CAN. The CAN-header is part of a CCP frame. CCP has to types
+of message objects. One is called Command Receive Object (CRO), the other is called
+Data Transmission Object (DTO). Usually CROs are sent to an ECU, and DTOs are received
+from an ECU. The information, if one DTO answers a CRO is implemented through a counter
+field (ctr). If both objects have the same counter value, the payload of a DTO object
+can be interpreted from the command of the associated CRO object.
+
+Creating a CRO message::
+
+    CCP(identifier=0x700)/CRO(ctr=1)/CONNECT(station_address=0x02)
+    CCP(identifier=0x711)/CRO(ctr=2)/GET_SEED(resource=2)
+    CCP(identifier=0x711)/CRO(ctr=3)/UNLOCK(key=b"123456")
+
+If we aren't interested in the DTO of an ECU, we can just send a CRO message like this:
+Sending a CRO message::
+
+    pkt = CCP(identifier=0x700)/CRO(ctr=1)/CONNECT(station_address=0x02)
+    sock = CANSocket(iface=can.interface.Bus(bustype='socketcan', channel='vcan0', bitrate=250000))
+    sock.send(pkt)
+
+If we are interested in the DTO of an ECU, we need to set the basecls parameter of the
+CANSocket to CCP and we need to use sr1:
+Sending a CRO message::
+
+    cro = CCP(identifier=0x700)/CRO(ctr=0x53)/PROGRAM_6(data=b"\x10\x11\x12\x10\x11\x12")
+    sock = CANSocket(iface=can.interface.Bus(bustype='socketcan', channel='vcan0', bitrate=250000), basecls=CCP)
+    dto = sock.sr1(cro)
+    dto.show()
+    ###[ CAN Calibration Protocol ]###
+      flags=
+      identifier= 0x700
+      length= 8
+      reserved= 0
+    ###[ DTO ]###
+         packet_id= 0xff
+         return_code= acknowledge / no error
+         ctr= 83
+    ###[ PROGRAM_6_DTO ]###
+            MTA0_extension= 2
+            MTA0_address= 0x34002006
+
+Since sr1 calls the answers function, our payload of the DTO objects gets interpreted with the
+command of our cro object.
+
 ISOTP message
 -------------
 
diff --git a/scapy/contrib/automotive/ccp.py b/scapy/contrib/automotive/ccp.py
new file mode 100644
index 00000000000..0aada0b6d2f
--- /dev/null
+++ b/scapy/contrib/automotive/ccp.py
@@ -0,0 +1,589 @@
+#! /usr/bin/env python
+
+# This file is part of Scapy
+# See http://www.secdev.org/projects/scapy for more information
+# Copyright (C) Nils Weiss <nils@we155.de>
+# This program is published under a GPLv2 license
+
+# scapy.contrib.description = CAN Calibration Protocol (CCP)
+# scapy.contrib.status = loads
+
+import struct
+
+from scapy.packet import Packet, bind_layers, bind_bottom_up
+from scapy.fields import XIntField, FlagsField, ByteEnumField, \
+    ThreeBytesField, XBitField, ShortField, IntField, XShortField, \
+    ByteField, XByteField, StrFixedLenField, LEShortField
+from scapy.layers.can import CAN
+
+
+class CCP(CAN):
+    name = 'CAN Calibration Protocol'
+    fields_desc = [
+        FlagsField('flags', 0, 3, ['error',
+                                   'remote_transmission_request',
+                                   'extended']),
+        XBitField('identifier', 0, 29),
+        ByteField('length', 8),
+        ThreeBytesField('reserved', 0),
+    ]
+
+    def extract_padding(self, p):
+        return p, None
+
+
+class CRO(Packet):
+    commands = {
+        0x01: "CONNECT",
+        0x1B: "GET_CCP_VERSION",
+        0x17: "EXCHANGE_ID",
+        0x12: "GET_SEED",
+        0x13: "UNLOCK",
+        0x02: "SET_MTA",
+        0x03: "DNLOAD",
+        0x23: "DNLOAD_6",
+        0x04: "UPLOAD",
+        0x0F: "SHORT_UP",
+        0x11: "SELECT_CAL_PAGE",
+        0x14: "GET_DAQ_SIZE",
+        0x15: "SET_DAQ_PTR",
+        0x16: "WRITE_DAQ",
+        0x06: "START_STOP",
+        0x07: "DISCONNECT",
+        0x0C: "SET_S_STATUS",
+        0x0D: "GET_S_STATUS",
+        0x0E: "BUILD_CHKSUM",
+        0x10: "CLEAR_MEMORY",
+        0x18: "PROGRAM",
+        0x22: "PROGRAM_6",
+        0x19: "MOVE",
+        0x05: "TEST",
+        0x09: "GET_ACTIVE_CAL_PAGE",
+        0x08: "START_STOP_ALL",
+        0x20: "DIAG_SERVICE",
+        0x21: "ACTION_SERVICE"
+    }
+    name = 'Command Receive Object'
+    fields_desc = [
+        ByteEnumField('cmd', 0x01, commands),
+        ByteField('ctr', 0)
+    ]
+
+    def hashret(self):
+        return struct.pack('B', self.ctr)
+
+
+# ##### CROs ######
+
+class CONNECT(Packet):
+    fields_desc = [
+        LEShortField('station_address', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 4, length=4),
+    ]
+
+
+bind_layers(CRO, CONNECT, cmd=0x01)
+
+
+class GET_CCP_VERSION(Packet):
+    fields_desc = [
+        XByteField('main_protocol_version', 0),
+        XByteField('release_version', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 4, length=4)
+    ]
+
+
+bind_layers(CRO, GET_CCP_VERSION, cmd=0x1B)
+
+
+class EXCHANGE_ID(Packet):
+    fields_desc = [
+        StrFixedLenField('ccp_master_device_id', b'\x00' * 6, length=6)
+    ]
+
+
+bind_layers(CRO, EXCHANGE_ID, cmd=0x17)
+
+
+class GET_SEED(Packet):
+    fields_desc = [
+        XByteField('resource', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 5, length=5)
+    ]
+
+
+bind_layers(CRO, GET_SEED, cmd=0x12)
+
+
+class UNLOCK(Packet):
+    fields_desc = [
+        StrFixedLenField('key', b'\x00' * 6, length=6)
+    ]
+
+
+bind_layers(CRO, UNLOCK, cmd=0x13)
+
+
+class SET_MTA(Packet):
+    fields_desc = [
+        XByteField('mta_num', 0),
+        XByteField('address_extension', 0),
+        XIntField('address', 0),
+    ]
+
+
+bind_layers(CRO, SET_MTA, cmd=0x02)
+
+
+class DNLOAD(Packet):
+    fields_desc = [
+        XByteField('size', 0),
+        StrFixedLenField('data', b'\x00' * 5, length=5)
+    ]
+
+
+bind_layers(CRO, DNLOAD, cmd=0x03)
+
+
+class DNLOAD_6(Packet):
+    fields_desc = [
+        StrFixedLenField('data', b'\x00' * 6, length=6)
+    ]
+
+
+bind_layers(CRO, DNLOAD_6, cmd=0x23)
+
+
+class UPLOAD(Packet):
+    fields_desc = [
+        XByteField('size', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 5, length=5)
+    ]
+
+
+bind_layers(CRO, UPLOAD, cmd=0x04)
+
+
+class SHORT_UP(Packet):
+    fields_desc = [
+        XByteField('size', 0),
+        XByteField('address_extension', 0),
+        XIntField('address', 0),
+    ]
+
+
+bind_layers(CRO, SHORT_UP, cmd=0x0F)
+
+
+class SELECT_CAL_PAGE(Packet):
+    fields_desc = [
+        StrFixedLenField('ccp_reserved', b'\xff' * 6, length=6)
+    ]
+
+
+bind_layers(CRO, SELECT_CAL_PAGE, cmd=0x11)
+
+
+class GET_DAQ_SIZE(Packet):
+    fields_desc = [
+        XByteField('DAQ_num', 0),
+        XByteField('ccp_reserved', 0),
+        XIntField('DTO_identifier', 0),
+    ]
+
+
+bind_layers(CRO, GET_DAQ_SIZE, cmd=0x14)
+
+
+class SET_DAQ_PTR(Packet):
+    fields_desc = [
+        XByteField('DAQ_num', 0),
+        XByteField('ODT_num', 0),
+        XByteField('ODT_element', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 3, length=3)
+    ]
+
+
+bind_layers(CRO, SET_DAQ_PTR, cmd=0x15)
+
+
+class WRITE_DAQ(Packet):
+    fields_desc = [
+        XByteField('DAQ_size', 0),
+        XByteField('address_extension', 0),
+        XIntField('address', 0),
+    ]
+
+
+bind_layers(CRO, WRITE_DAQ, cmd=0x16)
+
+
+class START_STOP(Packet):
+    fields_desc = [
+        XByteField('mode', 0),
+        XByteField('DAQ_num', 0),
+        XByteField('ODT_num', 0),
+        XByteField('event_channel', 0),
+        XShortField('transmission_rate', 0),
+    ]
+
+
+bind_layers(CRO, START_STOP, cmd=0x06)
+
+
+class DISCONNECT(Packet):
+    fields_desc = [
+        ByteEnumField('type', 0, {0: "temporary", 1: "end_of_session"}),
+        StrFixedLenField('ccp_reserved0', b'\xff' * 1, length=1),
+        LEShortField('station_address', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 2, length=2)
+    ]
+
+
+bind_layers(CRO, DISCONNECT, cmd=0x07)
+
+
+class SET_S_STATUS(Packet):
+    name = "Set Session Status"
+    fields_desc = [
+        FlagsField("session_status", 0, 8, ["CAL", "DAQ", "RESUME", "RES0",
+                                            "RES1", "RES2", "STORE", "RUN"]),
+        StrFixedLenField('ccp_reserved', b'\xff' * 5, length=5)
+    ]
+
+
+bind_layers(CRO, SET_S_STATUS, cmd=0x0C)
+
+
+class GET_S_STATUS(Packet):
+    fields_desc = [
+        StrFixedLenField('ccp_reserved', b'\xff' * 6, length=6)
+    ]
+
+
+bind_layers(CRO, GET_S_STATUS, cmd=0x0D)
+
+
+class BUILD_CHKSUM(Packet):
+    fields_desc = [
+        IntField('size', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 2, length=2)
+    ]
+
+
+bind_layers(CRO, BUILD_CHKSUM, cmd=0x0E)
+
+
+class CLEAR_MEMORY(Packet):
+    fields_desc = [
+        IntField('size', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 2, length=2)
+    ]
+
+
+bind_layers(CRO, CLEAR_MEMORY, cmd=0x10)
+
+
+class PROGRAM(Packet):
+    fields_desc = [
+        XByteField('size', 0),
+        StrFixedLenField('data', b'\x00' * 0,
+                         length_from=lambda pkt: pkt.size),
+        StrFixedLenField('ccp_reserved', b'\xff' * 5,
+                         length_from=lambda pkt: 5 - pkt.size)
+    ]
+
+
+bind_layers(CRO, PROGRAM, cmd=0x18)
+
+
+class PROGRAM_6(Packet):
+    fields_desc = [
+        StrFixedLenField('data', b'\x00' * 6, length=6)
+    ]
+
+
+bind_layers(CRO, PROGRAM_6, cmd=0x22)
+
+
+class MOVE(Packet):
+    fields_desc = [
+        IntField('size', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 2, length=2)
+    ]
+
+
+bind_layers(CRO, MOVE, cmd=0x19)
+
+
+class TEST(Packet):
+    fields_desc = [
+        LEShortField('station_address', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 4, length=4)
+    ]
+
+
+bind_layers(CRO, TEST, cmd=0x05)
+
+
+class GET_ACTIVE_CAL_PAGE(Packet):
+    fields_desc = [
+        StrFixedLenField('ccp_reserved', b'\xff' * 6, length=6)
+    ]
+
+
+bind_layers(CRO, GET_ACTIVE_CAL_PAGE, cmd=0x09)
+
+
+class START_STOP_ALL(Packet):
+    fields_desc = [
+        ByteEnumField('type', 0, {0: "stop", 1: "start"}),
+        StrFixedLenField('ccp_reserved', b'\xff' * 5, length=5)
+
+    ]
+
+
+bind_layers(CRO, START_STOP_ALL, cmd=0x08)
+
+
+class DIAG_SERVICE(Packet):
+    fields_desc = [
+        ShortField('diag_service', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 4, length=4)
+    ]
+
+
+bind_layers(CRO, DIAG_SERVICE, cmd=0x20)
+
+
+class ACTION_SERVICE(Packet):
+    fields_desc = [
+        ShortField('action_service', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 4, length=4)
+    ]
+
+
+bind_layers(CRO, ACTION_SERVICE, cmd=0x21)
+
+
+# ##### DTOs ######
+
+class DEFAULT_DTO(Packet):
+    fields_desc = [
+        StrFixedLenField('load', b'\xff' * 5, length=5),
+    ]
+
+
+class GET_CCP_VERSION_DTO(Packet):
+    fields_desc = [
+        XByteField('main_protocol_version', 0),
+        XByteField('release_version', 0),
+        StrFixedLenField('ccp_reserved', b'\x00' * 3, length=3)
+    ]
+
+
+class EXCHANGE_ID_DTO(Packet):
+    fields_desc = [
+        ByteField('slave_device_ID_length', 0),
+        ByteField('data_type_qualifier', 0),
+        ByteField('resource_availability_mask', 0),
+        ByteField('resource_protection_mask', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 1, length=1),
+    ]
+
+
+class GET_SEED_DTO(Packet):
+    fields_desc = [
+        XByteField('protection_status', 0),
+        StrFixedLenField('seed', b'\x00' * 4, length=4)
+    ]
+
+
+class UNLOCK_DTO(Packet):
+    fields_desc = [
+        ByteField('privilege_status', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 4, length=4),
+    ]
+
+
+class DNLOAD_DTO(Packet):
+    fields_desc = [
+        XByteField('MTA0_extension', 0),
+        XIntField('MTA0_address', 0)
+    ]
+
+
+class DNLOAD_6_DTO(Packet):
+    fields_desc = [
+        XByteField('MTA0_extension', 0),
+        XIntField('MTA0_address', 0)
+    ]
+
+
+class UPLOAD_DTO(Packet):
+    fields_desc = [
+        StrFixedLenField('data', b'\x00' * 5, length=5)
+    ]
+
+
+class SHORT_UP_DTO(Packet):
+    fields_desc = [
+        StrFixedLenField('data', b'\x00' * 5, length=5)
+    ]
+
+
+class GET_DAQ_SIZE_DTO(Packet):
+    fields_desc = [
+        XByteField('DAQ_list_size', 0),
+        XByteField('first_pid', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 3, length=3)
+    ]
+
+
+class GET_S_STATUS_DTO(Packet):
+    fields_desc = [
+        FlagsField("session_status", 0, 8, ["CAL", "DAQ", "RESUME", "RES0",
+                                            "RES1", "RES2", "STORE", "RUN"]),
+        ByteField('information_qualifier', 0),
+        StrFixedLenField('information', b'\x00' * 3, length=3)
+    ]
+
+
+class BUILD_CHKSUM_DTO(Packet):
+    fields_desc = [
+        ByteField('checksum_size', 0),
+        StrFixedLenField('checksum_data', b'\x00' * 4,
+                         length_from=lambda pkt: pkt.checksum_size),
+        StrFixedLenField('ccp_reserved', b'\xff' * 0,
+                         length_from=lambda pkt: 4 - pkt.checksum_size)
+    ]
+
+
+class PROGRAM_DTO(Packet):
+    fields_desc = [
+        ByteField('MTA0_extension', 0),
+        XIntField('MTA0_address', 0)
+    ]
+
+
+class PROGRAM_6_DTO(Packet):
+    fields_desc = [
+        ByteField('MTA0_extension', 0),
+        XIntField('MTA0_address', 0)
+    ]
+
+
+class GET_ACTIVE_CAL_PAGE_DTO(Packet):
+    fields_desc = [
+        XByteField('address_extension', 0),
+        XIntField('address', 0)
+    ]
+
+
+class DIAG_SERVICE_DTO(Packet):
+    fields_desc = [
+        ByteField('data_length', 0),
+        ByteField('data_type', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 3, length=3)
+    ]
+
+
+class ACTION_SERVICE_DTO(Packet):
+    fields_desc = [
+        ByteField('data_length', 0),
+        ByteField('data_type', 0),
+        StrFixedLenField('ccp_reserved', b'\xff' * 3, length=3)
+    ]
+
+
+class DTO(Packet):
+    __slots__ = Packet.__slots__ + ["payload_cls"]
+
+    return_codes = {
+        0x00: "acknowledge / no error",
+        0x01: "DAQ processor overload",
+        0x10: "command processor busy",
+        0x11: "DAQ processor busy",
+        0x12: "internal timeout",
+        0x18: "key request",
+        0x19: "session status request",
+        0x20: "cold start request",
+        0x21: "cal. data init. request",
+        0x22: "DAQ list init. request",
+        0x23: "code update request",
+        0x30: "unknown command",
+        0x31: "command syntax",
+        0x32: "parameter(s) out of range",
+        0x33: "access denied",
+        0x34: "overload",
+        0x35: "access locked",
+        0x36: "resource/function not available"
+    }
+    fields_desc = [
+        XByteField("packet_id", 0xff),
+        ByteEnumField('return_code', 0x00, return_codes),
+        ByteField('ctr', 0)
+    ]
+
+    def __init__(self, *args, **kwargs):
+        self.payload_cls = DEFAULT_DTO
+        if "payload_cls" in kwargs:
+            self.payload_cls = kwargs["payload_cls"]
+            del kwargs["payload_cls"]
+        Packet.__init__(self, *args, **kwargs)
+
+    def guess_payload_class(self, payload):
+        return self.payload_cls
+
+    @staticmethod
+    def get_dto_cls(cmd):
+        dto_cls_mapping = {
+            0x03: DNLOAD_DTO,
+            0x04: UPLOAD_DTO,
+            0x09: GET_ACTIVE_CAL_PAGE_DTO,
+            0x0D: GET_S_STATUS_DTO,
+            0x0E: BUILD_CHKSUM_DTO,
+            0x0F: SHORT_UP_DTO,
+            0x12: GET_SEED_DTO,
+            0x13: UNLOCK_DTO,
+            0x14: GET_DAQ_SIZE_DTO,
+            0x17: EXCHANGE_ID_DTO,
+            0x18: PROGRAM_DTO,
+            0x1B: GET_CCP_VERSION_DTO,
+            0x20: DIAG_SERVICE_DTO,
+            0x21: ACTION_SERVICE_DTO,
+            0x22: PROGRAM_6_DTO,
+            0x23: DNLOAD_6_DTO
+        }
+        return dto_cls_mapping[cmd] if cmd in dto_cls_mapping.keys() \
+            else DEFAULT_DTO
+
+    def answers(self, other):
+        """In CCP, the payload of a DTO packet is dependent on the cmd field
+        of a corresponding CRO packet. Two packets correspond, if there
+        ctr field is equal. If answers detect the corresponding CRO, it will
+        interpret the payload of a DTO with the correct class. In CCP, there is
+        no other way, to determine the class of a DTO payload. Since answers is
+        called on sr and sr1, this modification of the original answers
+        implementation will give a better user experience. """
+        if not hasattr(other, "ctr"):
+            return 0
+        if self.ctr != other.ctr:
+            return 0
+        if not hasattr(other, "cmd"):
+            return 0
+
+        new_pl_cls = self.get_dto_cls(other.cmd)
+        if self.payload_cls != new_pl_cls and \
+                self.payload_cls == DEFAULT_DTO:
+            data = bytes(self.load)
+            self.remove_payload()
+            self.add_payload(new_pl_cls(data))
+            self.payload_cls = new_pl_cls
+        return 1
+
+    def hashret(self):
+        return struct.pack('B', self.ctr)
+
+
+bind_bottom_up(CCP, DTO)
diff --git a/scapy/contrib/automotive/ccp.uts b/scapy/contrib/automotive/ccp.uts
new file mode 100644
index 00000000000..c5527e16d44
--- /dev/null
+++ b/scapy/contrib/automotive/ccp.uts
@@ -0,0 +1,998 @@
+% Regression tests for the CCP layer
+
+# More information at http://www.secdev.org/projects/UTscapy/
+
+
+############
+############
+
++ Basic operations
+
+= Load module
+
+load_contrib("automotive.ccp")
+
+= Build CRO CONNECT
+
+cro = CCP(identifier=0x700)/CRO(ctr=1)/CONNECT(station_address=0x02)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 1
+assert cro.cmd == 1
+assert cro.station_address == 0x02
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x01\x01\x02\x00\xff\xff\xff\xff'
+
+= Dissect DTO CONNECT
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x01\xff\xff\xff\xff\xff')
+
+assert dto.answers(cro)
+assert dto.identifier == 0x700
+assert dto.length == 8
+assert dto.flags == 0
+assert dto.ctr == 1
+assert dto.load == b"\xff" * 5
+
+= Build CRO EXCHANGE_ID
+
+cro = CCP(identifier=0x700)/CRO(ctr=18)/EXCHANGE_ID(ccp_master_device_id=b'abcdef')
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 18
+assert cro.cmd == 0x17
+assert cro.ccp_master_device_id == b"abcdef"
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x17\x12abcdef'
+
+= Dissect DTO EXCHANGE_ID
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x12\x04\x02\x03\x03\xff')
+
+assert dto.ctr == 18
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x04\x02\x03\x03\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 18
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.slave_device_ID_length == 4
+assert dto.data_type_qualifier == 2
+assert dto.resource_availability_mask == 3
+assert dto.resource_protection_mask == 3
+assert dto.ccp_reserved == b"\xff"
+
+= Build CRO GET_SEED
+
+cro = CCP(identifier=0x711)/CRO(ctr=19)/GET_SEED(resource=2)
+
+assert cro.identifier == 0x711
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 19
+assert cro.cmd == 0x12
+assert cro.resource == 2
+assert cro.ccp_reserved == b"\xff" * 5
+
+assert bytes(cro) == b'\x00\x00\x07\x11\x08\x00\x00\x00\x12\x13\x02\xff\xff\xff\xff\xff'
+
+= Dissect DTO GET_SEED
+
+dto = CCP(b'\x00\x00\x07\x11\x08\x00\x00\x00\xff\x00\x13\x01\x14\x15\x16\x17')
+
+assert dto.ctr == 19
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x01\x14\x15\x16\x17'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 19
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.protection_status == 0x1
+assert dto.seed == b'\x14\x15\x16\x17'
+
+= Build CRO UNLOCK
+
+cro = CCP(identifier=0x711)/CRO(ctr=20)/UNLOCK(key=b"123456")
+
+assert cro.identifier == 0x711
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 20
+assert cro.cmd == 0x13
+assert cro.key == b"123456"
+
+assert bytes(cro) == b'\x00\x00\x07\x11\x08\x00\x00\x00\x13\x14123456'
+
+= Dissect DTO UNLOCK
+
+dto = CCP(b'\x00\x00\x07\x11\x08\x00\x00\x00\xff\x00\x14\x02\xff\xff\xff\xff')
+
+assert dto.ctr == 20
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x02\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 20
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.privilege_status == 0x2
+assert dto.ccp_reserved == b"\xff" * 4
+
+= Build CRO SET_MTA
+
+cro = CCP(identifier=0x711)/CRO(ctr=21)/SET_MTA(mta_num=0, address_extension=0x02, address=0x34002000)
+
+assert cro.identifier == 0x711
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 21
+assert cro.cmd == 0x02
+assert cro.mta_num == 0
+assert cro.address_extension == 2
+assert cro.address == 0x34002000
+
+assert bytes(cro) == b'\x00\x00\x07\x11\x08\x00\x00\x00\x02\x15\x00\x02\x34\x00\x20\x00'
+
+= Dissect DTO SET_MTA
+
+dto = CCP(b'\x00\x00\x07\x11\x08\x00\x00\x00\xff\x00\x15\xff\xff\xff\xff\xff')
+
+assert dto.ctr == 21
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\xff\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 21
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == True
+assert dto.load == b"\xff" * 5
+
+= Build CRO DNLOAD
+
+cro = CCP(identifier=0x700)/CRO(ctr=17)/DNLOAD(size=0x05, data=b'abcde')
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 17
+assert cro.cmd == 3
+assert cro.size == 0x05
+assert cro.data == b'abcde'
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x03\x11\x05abcde'
+
+= Dissect DTO DNLOAD
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x11\x02\x34\x00\x20\x05')
+
+assert dto.ctr == 17
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x024\x00 \x05'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 17
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.MTA0_extension == 2
+assert dto.MTA0_address == 0x34002005
+
+= Build CRO DNLOAD_6
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x40)/DNLOAD_6(data=b'abcdef')
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x40
+assert cro.cmd == 0x23
+assert cro.data == b'abcdef'
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x23\x40abcdef'
+
+= Dissect DTO DNLOAD_6
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x40\x02\x34\x00\x20\x06')
+
+assert dto.ctr == 64
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x024\x00 \x06'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 64
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.MTA0_extension == 2
+assert dto.MTA0_address == 0x34002006
+
+= Build CRO UPLOAD
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x41)/UPLOAD(size=4)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x41
+assert cro.cmd == 0x04
+assert cro.size == 4
+assert cro.ccp_reserved == b"\xff" * 5
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x04\x41\x04\xff\xff\xff\xff\xff'
+
+= Dissect DTO UPLOAD
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x41\x10\x11\x12\x13\xff')
+
+assert dto.ctr == 65
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x10\x11\x12\x13\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 65
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.data == b"\x10\x11\x12\x13\xff"
+
+= Build CRO SHORT_UP
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x42)/SHORT_UP(size=4, address_extension=0, address=0x12345678)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x42
+assert cro.cmd == 0x0f
+assert cro.size == 4
+assert cro.address == 0x12345678
+assert cro.address_extension == 0
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x0f\x42\x04\x00\x12\x34\x56\x78'
+
+= Dissect DTO SHORT_UP
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x42\x10\x11\x12\x13\xff')
+
+assert dto.ctr == 66
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x10\x11\x12\x13\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 66
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.data == b"\x10\x11\x12\x13\xff"
+
+= Build CRO SELECT_CAL_PAGE
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x43)/SELECT_CAL_PAGE()
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x43
+assert cro.cmd == 0x11
+assert cro.ccp_reserved == b"\xff" * 6
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x11\x43\xff\xff\xff\xff\xff\xff'
+
+= Dissect DTO SELECT_CAL_PAGE
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x43\xff\xff\xff\xff\xff')
+
+assert dto.ctr == 67
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\xff\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 67
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == True
+assert dto.load == b"\xff\xff\xff\xff\xff"
+
+= Build CRO GET_DAQ_SIZE
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x44)/GET_DAQ_SIZE(DAQ_num=0x03, DTO_identifier=0x1020304)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x44
+assert cro.cmd == 0x14
+assert cro.DAQ_num == 0x03
+assert cro.ccp_reserved == 00
+assert cro.DTO_identifier == 0x01020304
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x14\x44\x03\x00\x01\x02\x03\x04'
+
+= Dissect DTO GET_DAQ_SIZE
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x44\x10\x08\xff\xff\xff')
+
+assert dto.ctr == 68
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x10\x08\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 68
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.DAQ_list_size == 16
+assert dto.first_pid == 8
+assert dto.ccp_reserved == b"\xff\xff\xff"
+
+= Build CRO SET_DAQ_PTR
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x45)/SET_DAQ_PTR(DAQ_num=3, ODT_num=5, ODT_element=2)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x45
+assert cro.cmd == 0x15
+assert cro.DAQ_num == 0x03
+assert cro.ODT_num == 5
+assert cro.ODT_element == 2
+assert cro.ccp_reserved == b"\xff\xff\xff"
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x15\x45\x03\x05\x02\xff\xff\xff'
+
+= Dissect DTO SET_DAQ_PTR
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x45\xff\xff\xff\xff\xff')
+
+assert dto.ctr == 69
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\xff\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 69
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == True
+assert dto.load == b'\xff\xff\xff\xff\xff'
+
+= Build CRO WRITE_DAQ
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x46)/WRITE_DAQ(DAQ_size=2, address_extension=1, address=0x2004200)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x46
+assert cro.cmd == 0x16
+assert cro.DAQ_size == 0x02
+assert cro.address_extension == 1
+assert cro.address == 0x2004200
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x16\x46\x02\x01\x02\x00\x42\x00'
+
+= Dissect DTO WRITE_DAQ
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x46\xff\xff\xff\xff\xff')
+
+assert dto.ctr == 70
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\xff\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 70
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == True
+assert dto.load == b'\xff\xff\xff\xff\xff'
+
+= Build CRO START_STOP
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x47)/START_STOP(mode=1, DAQ_num=3, ODT_num=7, event_channel=2, transmission_rate=1)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x47
+assert cro.cmd == 0x06
+assert cro.mode == 0x01
+assert cro.DAQ_num == 3
+assert cro.event_channel == 2
+assert cro.transmission_rate == 1
+assert cro.ODT_num == 7
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x06\x47\x01\x03\x07\x02\x00\x01'
+
+= Dissect DTO START_STOP
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x47\xff\xff\xff\xff\xff')
+
+assert dto.ctr == 71
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\xff\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 71
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == True
+assert dto.load == b'\xff\xff\xff\xff\xff'
+
+= Build CRO DISCONNECT
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x48)/DISCONNECT(type="temporary", station_address=0x208)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x48
+assert cro.cmd == 0x07
+assert cro.type == 0x00
+assert cro.station_address == 0x208
+assert cro.ccp_reserved0 == b"\xff"
+assert cro.ccp_reserved == b"\xff" * 2
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x07\x48\x00\xff\x08\x02\xff\xff'
+
+= Dissect DTO DISCONNECT
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x48\xff\xff\xff\xff\xff')
+
+assert dto.ctr == 72
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\xff\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 72
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == True
+assert dto.load == b'\xff\xff\xff\xff\xff'
+
+= Build CRO SET_S_STATUS
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x49)/SET_S_STATUS(session_status="RUN+CAL")
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x49
+assert cro.cmd == 0x0c
+assert cro.session_status == 0x81
+assert cro.ccp_reserved == b"\xff" * 5
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x0c\x49\x81\xff\xff\xff\xff\xff'
+
+= Dissect DTO SET_S_STATUS
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x49\xff\xff\xff\xff\xff')
+
+assert dto.ctr == 73
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\xff\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 73
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == True
+assert dto.load == b'\xff\xff\xff\xff\xff'
+
+= Build CRO GET_S_STATUS
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x4a)/GET_S_STATUS()
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x4a
+assert cro.cmd == 0x0D
+assert cro.ccp_reserved == b"\xff" * 6
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x0d\x4a\xff\xff\xff\xff\xff\xff'
+
+= Dissect DTO GET_S_STATUS
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x4a\x81\xff\xff\xff\xff')
+
+assert dto.ctr == 74
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x81\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 74
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.session_status == 0x81
+assert dto.information_qualifier == 0xff
+assert dto.information == b"\xff" * 3
+
+= Build CRO BUILD_CHKSUM
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x50)/BUILD_CHKSUM(size=0x8000)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x50
+assert cro.cmd == 0x0e
+assert cro.size == 0x8000
+assert cro.ccp_reserved == b"\xff" * 2
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x0e\x50\x00\x00\x80\x00\xff\xff'
+
+= Dissect DTO BUILD_CHKSUM
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x50\x02\x12\x34\xff\xff')
+
+assert dto.ctr == 80
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x02\x12\x34\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 80
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.checksum_size == 2
+assert dto.checksum_data == b'\x12\x34'
+assert dto.ccp_reserved == b'\xff\xff'
+
+= Dissect DTO BUILD_CHKSUM2
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x50\x04\x12\x34\x56\x78')
+
+assert dto.ctr == 80
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x04\x12\x34\x56\x78'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 80
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.checksum_size == 4
+assert dto.checksum_data == b'\x12\x34\x56\x78'
+assert dto.ccp_reserved == b''
+
+= Build CRO CLEAR_MEMORY
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x51)/CLEAR_MEMORY(size=0x8000)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x51
+assert cro.cmd == 0x10
+assert cro.size == 0x8000
+assert cro.ccp_reserved == b"\xff" * 2
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x10\x51\x00\x00\x80\x00\xff\xff'
+
+= Dissect DTO CLEAR_MEMORY
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x51\xff\xff\xff\xff\xff')
+
+assert dto.ctr == 81
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\xff\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 81
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == True
+assert dto.load == b'\xff\xff\xff\xff\xff'
+
+= Build CRO PROGRAM
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x52)/PROGRAM(size=0x3, data=b"\x10\x11\x12")
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x52
+assert cro.cmd == 0x18
+assert cro.size == 0x3
+assert cro.data == b"\x10\x11\x12"
+assert cro.ccp_reserved == b"\xff" * 5
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x18\x52\x03\x10\x11\x12\xff\xff'
+
+= Dissect DTO PROGRAM
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x52\x02\x34\x00\x20\x03')
+
+assert dto.ctr == 82
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x02\x34\x00\x20\x03'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 82
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.MTA0_extension == 2
+assert dto.MTA0_address == 0x34002003
+
+= Build CRO PROGRAM_6
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x53)/PROGRAM_6(data=b"\x10\x11\x12\x10\x11\x12")
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x53
+assert cro.cmd == 0x22
+assert cro.data == b"\x10\x11\x12\x10\x11\x12"
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x22\x53\x10\x11\x12\x10\x11\x12'
+
+= Dissect DTO PROGRAM_6
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x53\x02\x34\x00\x20\x06')
+
+assert dto.ctr == 83
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x02\x34\x00\x20\x06'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 83
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.MTA0_extension == 2
+assert dto.MTA0_address == 0x34002006
+
+= Build CRO MOVE
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x54)/MOVE(size=0x8000)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x54
+assert cro.cmd == 0x19
+assert cro.size == 0x8000
+assert cro.ccp_reserved == b'\xff\xff'
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x19\x54\x00\x00\x80\x00\xff\xff'
+
+= Dissect DTO MOVE
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x54\xff\xff\xff\xff\xff')
+
+assert dto.ctr == 84
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\xff\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 84
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == True
+
+= Build CRO DIAG_SERVICE
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x55)/DIAG_SERVICE(diag_service=0x8000)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x55
+assert cro.cmd == 0x20
+assert cro.diag_service == 0x8000
+assert cro.ccp_reserved == b'\xff\xff\xff\xff'
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x20\x55\x80\x00\xff\xff\xff\xff'
+
+= Dissect DTO DIAG_SERVICE
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x55\x20\x00\xff\xff\xff')
+
+assert dto.ctr == 85
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x20\x00\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 85
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.data_length == 0x20
+assert dto.data_type == 0x00
+assert dto.ccp_reserved == b"\xff\xff\xff"
+
+= Build CRO ACTION_SERVICE
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x56)/ACTION_SERVICE(action_service=0x8000)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x56
+assert cro.cmd == 0x21
+assert cro.action_service == 0x8000
+assert cro.ccp_reserved == b'\xff\xff\xff\xff'
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x21\x56\x80\x00\xff\xff\xff\xff'
+
+= Dissect DTO ACTION_SERVICE
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x56\x20\x00\xff\xff\xff')
+
+assert dto.ctr == 86
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x20\x00\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 86
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.data_length == 0x20
+assert dto.data_type == 0x00
+assert dto.ccp_reserved == b"\xff\xff\xff"
+
+= Build CRO TEST
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x60)/TEST(station_address=0x80)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x60
+assert cro.cmd == 0x05
+assert cro.station_address == 0x80
+assert cro.ccp_reserved == b"\xff" * 4
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x05\x60\x80\x00\xff\xff\xff\xff'
+
+= Dissect DTO TEST
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x60\xff\xff\xff\xff\xff')
+
+assert dto.ctr == 96
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\xff\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 96
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == True
+assert dto.load == b'\xff\xff\xff\xff\xff'
+
+= Build CRO START_STOP_ALL
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x61)/START_STOP_ALL(type="start")
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x61
+assert cro.cmd == 0x08
+assert cro.type == 0x01
+assert cro.ccp_reserved == b"\xff" * 5
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x08\x61\x01\xff\xff\xff\xff\xff'
+
+= Dissect DTO START_STOP_ALL
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x61\xff\xff\xff\xff\xff')
+
+assert dto.ctr == 97
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\xff\xff\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 97
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == True
+assert dto.load == b'\xff\xff\xff\xff\xff'
+
+= Build CRO GET_ACTIVE_CAL_PAGE
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x62)/GET_ACTIVE_CAL_PAGE()
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x62
+assert cro.cmd == 0x09
+assert cro.ccp_reserved == b"\xff" * 6
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x09\x62\xff\xff\xff\xff\xff\xff'
+
+= Dissect DTO GET_ACTIVE_CAL_PAGE
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x62\x01\x11\x44\x77\x22')
+
+assert dto.ctr == 98
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x01\x11\x44\x77\x22'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 98
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.address_extension == 1
+assert dto.address == 0x11447722
+
+= Build CRO GET_CCP_VERSION
+
+cro = CCP(identifier=0x700)/CRO(ctr=0x63)/GET_CCP_VERSION(main_protocol_version=2, release_version=1)
+
+assert cro.identifier == 0x700
+assert cro.length == 8
+assert cro.flags == 0
+assert cro.ctr == 0x63
+assert cro.cmd == 0x1b
+assert cro.main_protocol_version == 2
+assert cro.release_version == 1
+assert cro.ccp_reserved == b"\xff" * 4
+assert bytes(cro) == b'\x00\x00\x07\x00\x08\x00\x00\x00\x1b\x63\x02\x01\xff\xff\xff\xff'
+
+assert dto.hashret() != cro.hashret()
+assert not dto.answers(cro)
+
+= Dissect DTO GET_CCP_VERSION
+
+dto = CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x63\x02\x01\xff\xff\xff')
+
+assert dto.ctr == 99
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert dto.load == b'\x02\x01\xff\xff\xff'
+# answers will interpret payload
+assert dto.answers(cro)
+assert dto.ctr == 99
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.main_protocol_version == 2
+assert dto.release_version == 1
+assert dto.ccp_reserved == b"\xff" * 3
+
+assert dto.hashret() == cro.hashret()
+
++ Tests on a virtual CAN-Bus
+~ needs_root linux
+
+= Load modules
+~ needs_root linux conf
+import can
+from subprocess import call
+import time
+
+conf.contribs['CANSocket'] = {'use-python-can': True}
+load_contrib("cansocket")
+
+iface0 = "vcan0"
+
+= Initialize a virtual CAN interface
+~ needs_root linux conf
+if 0 != call("cansend %s 000#" % iface0, shell=True):
+    # vcan0 is not enabled
+    if 0 != call("sudo modprobe vcan", shell=True):
+        raise Exception("modprobe vcan failed")
+    if 0 != call("sudo ip link add name %s type vcan" % iface0, shell=True):
+        print("add %s failed: Maybe it was already up?" % iface0)
+    if 0 != call("sudo ip link set dev %s up" % iface0, shell=True):
+        raise Exception("could not bring up %s" % iface0)
+
+if 0 != call("cansend %s 000#" % iface0, shell=True):
+    raise Exception("cansend doesn't work")
+
+print("CAN should work now")
+
+= CAN Socket sr1 with dto.ansers(cro) == True
+~ needs_root linux
+
+sock1 = CANSocket(iface=can.interface.Bus(bustype='socketcan', channel='vcan0', bitrate=250000), basecls=CCP)
+sock2 = CANSocket(iface=can.interface.Bus(bustype='socketcan', channel='vcan0', bitrate=250000))
+
+def ecu():
+    pkts = sock2.sniff(count=1, timeout=1)
+    if len(pkts) == 1:
+        cro = CRO(pkts[0].data)
+        assert cro.cmd == 0x22
+        assert cro.data == b"\x10\x11\x12\x10\x11\x12"
+        sock2.send(CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x53\x02\x34\x00\x20\x06'))
+
+
+thread = threading.Thread(target=ecu)
+thread.start()
+time.sleep(0.1)
+
+dto = sock1.sr1(CCP(identifier=0x700)/CRO(ctr=0x53)/PROGRAM_6(data=b"\x10\x11\x12\x10\x11\x12"), timeout=1)
+thread.join()
+
+assert dto.ctr == 83
+assert dto.packet_id == 0xff
+assert dto.return_code == 0
+assert hasattr(dto, "load") == False
+assert dto.MTA0_extension == 2
+assert dto.MTA0_address == 0x34002006
+
+sock1.close()
+sock2.close()
+
+
+= CAN Socket sr1 with dto.ansers(cro) == False
+~ needs_root linux
+
+sock1 = CANSocket(iface=can.interface.Bus(bustype='socketcan', channel='vcan0', bitrate=250000), basecls=CCP)
+sock2 = CANSocket(iface=can.interface.Bus(bustype='socketcan', channel='vcan0', bitrate=250000))
+
+def ecu():
+    pkts = sock2.sniff(count=1, timeout=1)
+    if len(pkts) == 1:
+        cro = CRO(pkts[0].data)
+        assert cro.cmd == 0x22
+        assert cro.data == b"\x10\x11\x12\x10\x11\x12"
+        sock2.send(CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x00\x55\x02\x34\x00\x20\x06'))
+
+
+thread = threading.Thread(target=ecu)
+thread.start()
+time.sleep(0.1)
+gotTimeout = False
+try:
+    dto = sock1.sr1(CCP(identifier=0x700)/CRO(ctr=0x54)/PROGRAM_6(data=b"\x10\x11\x12\x10\x11\x12"), timeout=1)
+except CANSocketTimeoutElapsed as e:
+    gotTimeout = True
+
+assert gotTimeout
+thread.join()
+
+sock1.close()
+sock2.close()
+
+= CAN Socket sr1 with error code
+~ needs_root linux
+
+sock1 = CANSocket(iface=can.interface.Bus(bustype='socketcan', channel='vcan0', bitrate=250000), basecls=CCP)
+sock2 = CANSocket(iface=can.interface.Bus(bustype='socketcan', channel='vcan0', bitrate=250000))
+
+def ecu():
+    pkts = sock2.sniff(count=1, timeout=1)
+    if len(pkts) == 1:
+        cro = CRO(pkts[0].data)
+        assert cro.cmd == 0x22
+        assert cro.data == b"\x10\x11\x12\x10\x11\x12"
+        sock2.send(CCP(b'\x00\x00\x07\x00\x08\x00\x00\x00\xff\x01\x55\xff\xff\xff\xff\xff'))
+
+
+thread = threading.Thread(target=ecu)
+thread.start()
+time.sleep(0.1)
+
+dto = sock1.sr1(CCP(identifier=0x700)/CRO(ctr=0x55)/PROGRAM_6(data=b"\x10\x11\x12\x10\x11\x12"), timeout=1)
+thread.join()
+
+assert dto.ctr == 85
+assert dto.packet_id == 0xff
+assert dto.return_code == 1
+assert hasattr(dto, "load") == False
+assert dto.MTA0_extension == 0xff
+assert dto.MTA0_address == 0xffffffff
+
+sock1.close()
+sock2.close()
\ No newline at end of file
diff --git a/scapy/contrib/cansocket_python_can.py b/scapy/contrib/cansocket_python_can.py
index e1bfd5a446a..c62fde289f6 100644
--- a/scapy/contrib/cansocket_python_can.py
+++ b/scapy/contrib/cansocket_python_can.py
@@ -71,7 +71,7 @@ def send(self, x):
                               is_error_frame=x.flags == 0x1,
                               arbitration_id=x.identifier,
                               dlc=x.length,
-                              data=x.data)
+                              data=bytes(x)[8:])
             return self.iface.send(msg)
         except can_Error as ex:
             raise ex