Commission Implementing Regulation (EU) 2016/799Show full title

2.2.2 Message types U.K.

The communication protocol for data download between the VU and the IDE requires the exchange of 8 different message types.

The following table summarises these messages.

[F1 Message Structure		Max 4 Bytes Header				Max 255 Bytes Data			1 Byte CheckSum
IDE ->	<- VU	FMT	TGT	SRC	LEN	SID	DS_ / TRTP	DATA	CS
Start Communication Request		81	EE	F0		81			E0
Positive Response Start Communication		80	F0	EE	03	C1		EA, 8F	9B
Start Diagnostic Session Request		80	EE	F0	02	10	81		F1
Positive Response Start Diagnostic		80	F0	EE	02	50	81		31
Link Control Service
Verify Baud Rate (stage 1)
9 600 Bd		80	EE	F0	04	87		01,01,01	EC
19 200 Bd		80	EE	F0	04	87		01,01,02	ED
38 400 Bd		80	EE	F0	04	87		01,01,03	EE
57 600 Bd		80	EE	F0	04	87		01,01,04	EF
115 200 Bd		80	EE	F0	04	87		01,01,05	F0
Positive Response Verify Baud Rate		80	F0	EE	02	C7		01	28
Transition Baud Rate (stage 2)		80	EE	F0	03	87		02,03	ED
Request Upload		80	EE	F0	0A	35		00,00,00,00,00,FF,FF, FF,FF	99
Positive Response Request Upload		80	F0	EE	03	75		00,FF	D5
Transfer Data Request
Overview		80	EE	F0	02	36	01 or 21		97
Activities		80	EE	F0	06	36	02 or 22	Date	CS
Events & Faults		80	EE	F0	02	36	03 or 23	Date	99
Detailed Speed		80	EE	F0	02	36	04 or 24	Date	9 A
Technical Data		80	EE	F0	02	36	05 or 25	Date	9B
Card download		80	EE	F0	02	36	06	Slot	CS
Positive Response Transfer Data		80	F0	EE	Len	76	TREP	Data	CS
Request Transfer Exit		80	EE	F0	01	37			96
Positive Response Request Transfer Exit		80	F0	EE	01	77			D6
Stop Communication Request		80	EE	F0	01	82			E1
Positive Response Stop Communication		80	F0	EE	01	C2			21
Acknowledge sub message		80	EE	F0	Len	83		Data	CS
Negative responses
General reject		80	F0	EE	03	7F	Sid Req	10	CS
Service not supported		80	F0	EE	03	7F	Sid Req	11	CS
Sub function not supported		80	F0	EE	03	7F	Sid Req	12	CS
Incorrect Message Length		80	F0	EE	03	7F	Sid Req	13	CS
Conditions not correct or Request sequence error		80	F0	EE	03	7F	Sid Req	22	CS
Request out of range		80	F0	EE	03	7F	Sid Req	31	CS
Upload not accepted		80	F0	EE	03	7F	Sid Req	50	CS
Response pending		80	F0	EE	03	7F	Sid Req	78	CS
Data not available		80	F0	EE	03	7F	Sid Req	FA	CS]

Textual Amendments

F1 Substituted by Commission Implementing Regulation (EU) 2018/502 of 28 February 2018 amending Implementing Regulation (EU) 2016/799 laying down the requirements for the construction, testing, installation, operation and repair of tachographs and their components (Text with EEA relevance).

Notes: U.K.

• [F2 TRTP 21 to 25 are used for Generation 2 type of VU data download requests, TRTP 01 to 05 are used for Generation 1 type of VU data download requests, which can only be accepted by the VU in the frame of drivers' control performed by a non EU control authority, using a first generation control card.

• TRTP 11 to 19 and 31 to 39 are reserved for manufacturer specific download requests.]

• Sid Req = the Sid of the corresponding request.

• TREP = the TRTP of the corresponding request.

• Dark cells denote that nothing is transmitted.

• The term upload (as seen from the IDE) is used for compatibility with ISO 14229. It means the same as download (as seen from the VU).

• Potential 2-byte sub message counters are not shown in this table.

• Slot is the slot number, either “1” (card on driver slot) or “2” (card on co-driver slot)

• In case the slot is not specified, the VU shall select slot 1 if a card is inserted in this slot and it shall select slot 2 only in case it is specifically selected by the user.

2.2.2.1 Start Communication Request (SID 81) U.K.

DDP_005 This message is issued by the IDE to establish the communication link with the VU. Initial communications are always performed at 9 600 baud (until baud rate is eventually changed using the appropriate Link control services). U.K.

2.2.2.2 Positive Response Start Communication (SID C1) U.K.

DDP_006 This message is issued by the VU to answer positively to a start communication request. It includes the 2 key bytes ‘EA’‘8F’ indicating that the unit supports protocol with header including target source and length information. U.K.

2.2.2.3 Start Diagnostic Session Request (SID 10) U.K.

DDP_007 The Start Diagnostic Session request message is issued by the IDE in order to request a new diagnostic session with the VU. The sub function ‘default session’ (81 Hex) indicates a standard diagnostic session is to be opened. U.K.

2.2.2.4 Positive Response Start Diagnostic (SID 50) U.K.

DDP_008 The Positive Response Start Diagnostic message is sent by the VU to answer positively to Diagnostic Session Request. U.K.

2.2.2.5 Link Control Service (SID 87) U.K.

DDP_052 The Link Control Service is used by the IDE to initiate a change in baud rate. This takes place in two steps. In step one the IDE proposes the baud rate change, indicating the new rate. On receipt of a positive message from the VU the IDE sends out confirmation of the baud rate change to the VU (step two). The IDE then changes to the new baud rate. After receipt of the confirmation the VU changes to the new baud rate U.K.

2.2.2.6 Link Control Positive Response (SID C7) U.K.

DDP_053 The Link Control Positive Response is issued by the VU to answer positively to Link Control Service request (step one). Note that no response is given to the confirmation request (step two). U.K.

2.2.2.7 Request Upload (SID 35) U.K.

DDP_009 The Request Upload message is issued by the IDE to specify to the VU that a download operation is requested. To meet the requirements of ISO14229 data is included covering address, the size and format details for the data requested. As these are not known to the IDE prior to a download, the memory address is set to 0, format is unencrypted and uncompressed and the memory size is set to the maximum. U.K.

2.2.2.8 Positive Response Request Upload (SID 75) U.K.

DDP_010 The Positive Response Request Upload message is sent by the VU to indicate to the IDE that the VU is ready to download data. To meet the requirements of ISO 14229 data is included in this positive response message, indicating to the IDE that further Positive Response Transfer Data messages will include 00FF hex bytes maximum. U.K.

2.2.2.9 Transfer Data Request (SID 36) U.K.

[F1 DDP_011 The Transfer Data Request is sent by the IDE to specify to the VU the type of data that are to be downloaded. A one byte Transfer Request Parameter (TRTP) indicates the type of transfer. U.K.

There are six types of data transfer. For VU data download, two different TRTP values can be used for each transfer type:

Data transfer type	TRTP value for generation 1 type of VU data download	TRTP value for generation 2 type of VU data download
Overview	01	21
Activities of a specified date	02	22
Events and faults	03	23
Detailed speed	04	24
Technical data	05	25

Data transfer type	TRTP value
Card download	06]

[F1 DDP_054 It is mandatory for the IDE to request the overview data transfer (TRTP 01 or 21) during a download session as this only will ensure that the VU certificates are recorded within the downloaded file (and allow for verification of digital signature). U.K.

In the second case (TRTP 02 or 22) the Transfer Data Request message includes the indication of the calendar day ( format) to be downloaded.]

2.2.2.10 Positive Response Transfer Data (SID 76) U.K.

DDP_012 The Positive Response Transfer Data is sent by the VU in response to the Transfer Data Request. The message contains the requested data, with a Transfer Response Parameter (TREP) corresponding to the TRTP of the request. U.K.

[F1 DDP_055 In the first case (TREP 01 or 21), the VU will send data helping the IDE operator to choose the data he wants to download further. The information contained within this message is: U.K.

• Security certificates,

• Vehicle identification,

• VU current date and time,

• Min and Max downloadable date (VU data),

• Indication of cards presence in the VU,

• Previous download to a company,

• Company locks,

• Previous controls.]

2.2.2.11 Request Transfer Exit (SID 37) U.K.

DDP_013 The Request Transfer Exit message is sent by the IDE to inform the VU that the download session is terminated. U.K.

2.2.2.12 Positive Response Request Transfer Exit (SID 77) U.K.

DDP_014 The Positive Response Request Transfer Exit message is sent by the VU to acknowledge the Request Transfer Exit. U.K.

2.2.2.13 Stop Communication Request (SID 82) U.K.

DDP_015 The Stop Communication Request message is sent by the IDE to disconnect the communication link with the VU. U.K.

2.2.2.14 Positive Response Stop Communication (SID C2) U.K.

DDP_016 The Positive Response Stop Communication message is sent by the VU to acknowledge the Stop Communication Request. U.K.

2.2.2.15 Acknowledge Sub Message (SID 83) U.K.

DDP_017 The Acknowledge Sub Message is sent by the IDE to confirm receipt of each part of a message that is being transmitted as several sub messages. The data field contains the SID received from the VU and a 2-byte code as follows: U.K.

• MsgC+1 Acknowledges correct receipt of sub message number MsgC.

  Request from the IDE to the VU to send next sub message

• MsgC indicates a problem with the receipt of sub message number MsgC.

  Request from the IDE to the VU to send the sub message again.

• FFFF requests termination of the message.

  This can be used by the IDE to end the transmission of the VU message for any reason.

The last sub message of a message (LEN byte < 255) may be acknowledged using any of these codes or not acknowledged.

The VU responses that will consist of several sub messages are:

• Positive Response Transfer Data (SID 76)

2.2.2.16 Negative Response (SID 7F) U.K.

DDP_018 The Negative Response message is sent by the VU in response to the above request messages when the VU cannot satisfy the request. The data fields of the message contains the SID of the response (7F), the SID of the request, and a code specifying the reason of the negative response. The following codes are available: U.K.

• 10 general reject

  The action cannot be performed for a reason not covered below.

• 11 service not supported

  The SID of the request is not understood.

• 12 sub function not supported

  The DS_ or TRTP of the request is not understood, or there are no further sub messages to be transmitted.

• 13 incorrect message length

  The length of the received message is wrong.

• 22 conditions not correct or request sequence error

  The required service is not active or the sequence of request messages is not correct.

• 31 Request out of range

  The request parameter record (data field) is not valid.

• 50 upload not accepted

  The request cannot be performed (VU in a non appropriate mode of operation or internal fault of the VU).

• 78 response pending

  The action requested cannot be completed in time and the VU is not ready to accept another request.

• [F1 FA data not available

  The data object of a data transfer request are not available in the VU (e.g. no card is inserted, generation 1 type of VU data download requested outside the frame of a driver’s control by a non EU control authority…).]