CAN dictionary

Explains vocabulary and abbreviations used in CAN technology

Alphabetic selection:


data bit rate

Number of bits per time during data phase of a CAN FD frame. The data bit rate is independent of bit encoding/decoding.

data bit time

Duration of one bit in the data phase of a CAN FD frame. The data bit time has the same length as the nominal bit time or is shorter than the nominal bit time.

data consistency

With regard to network technologies, data consistency means that all devices, which are connected to the same network, have the same state of knowledge. Network­ wide data consistency is guaranteed for all error active CAN nodes by means of globalization of local errors.

data field

The data field of the CAN data frame contains 0 to including 8 byte of user information in Classical CAN frames or 0 to including 64 byte in CAN FD frames, where each byte contains 8 bit. The data size is indicated by the DLC.

data frame (OF)

The CAN data frame carries user data from a producer to one or more consumers. It consists of the start of frame (SOF) bit, the arbitration field, the control field, the data field, the CRC field, the acknowledge (ACK) field, and the end of frame (EOF) field.

data length code (DLC)

4-bit DLC in the control field of CAN data frame indicates the data field length. In remote frames (only Classical CAN) the DLC corresponds to the data field length in the requested data frame!

data link layer

Second layer in the OSI reference model providing basic communication services. The CAN data link layer defines data, remote (only in Classical CAN), error, and overload frames.

data phase

The data phase indicates those parts of the CAN FD data frame that are transmitted with a higher bit rate. It is wrapped by the arbitration phase, and starts with the sample point of the BRS bit and lasts till the sample point of the CRC delimiter.

data type

Object attribute in CAN open and DeviceNet defining the format, e.g. Unsigned8, Integer16, Boolean, etc.


The Distributor is part of the CAN Application Layer (CAL) specification defining a method of automatic identifier distribution during network boot-up.


See device configuration file.

default value

Object attribute in CANopen defining the pre-setting of not user-configured objects after power-on or application reset.

destination address mode (DAM)

In the DAM mode of a CANopen MPDO, a multiplexer identifies the object (16-bit index and 8-bit sub-index) in the MPDO consumer's object dictionary.

device configuration file (DCF)

The device configuration file describes the CANopen parameter of a configured CAN open device in the same file format as the EDS.

device profile

A device profile defines the device-specific application data and communication capability based on the related higher­ layer protocol. For more complex devices these profiles may provide a finite state automaton (FSA), which enables standardized device control.


CAN-based higher-layer protocol and device profiles definition. DeviceNet was designed for factory automation and provides a well-defined CAN physical layer in order to achieve a high off­ the-shelf plug-and-play capability. The DeviceNet specification is maintained by the ODVA ( non-profit organization.

Diagnostic message

A diagnostic message is a diagnostic service (request or response) that contains a diagnostic service identifier (SID).

Diagnostic routine

The diagnostic routine is a part of the ECU application software, It supports diagnostic communication and is enabled by the tester.

Diagnostic session

A session is a specific state of the ECU. A typical example of a diagnostic session is the default session. The session definition includes the diagnostic services supported by the ECU. The tester can request session transitions.

Diagnostics on CAN

The ISO 15765 standard defines the Diagnostic on CAN protocols and services, which are used for the CAN­ based diagnostic interface for passenger cars.


See data length code.

dominant bit

Bit on the CAN bus lines representing dominant state. It has the logical value O. A dominant bit overwrites by definition a recessive bit.

double­ reception of message

If the last bit of the end of frame (EOF) is corrupted at the transmitting node, then a retransmission of the message is caused. Since the receivers have already accepted the message after the last but one bit, they will receive the message twice.

DR (draft recommendation)

This kind of recommendation is not finalized, but it is published. CiA's DRs are not changed within one year.

DS (draft standard)

This kind of specification is not finalized, but it is published. CiA's DSs are not changed within one year.

DSP (draft standard proposal)

This kind of specification is a proposal, but it is published. CiA's DSPs may be changed anytime without notification.

D-sub connectors

Standardized connectors. Most common in use is the 9-pin D-sub connector (DIN 41652); its pin-assignment for CAN/ CANopen networks is recommended in CiA 303-1.

Source CANdictionary (2016) - CiA CAN in Automation -