CAN dictionary

Explains vocabulary and abbreviations used in CAN technology

Alphabetic selection:



See transmit error counter.

termination resistor

In CAN high-speed networks with bus line topology, both ends are terminated with resistors (120 0) in order to suppress reflections.

thick cable

The thick cable is specified in the physical layer definitions of the DeviceNet specification. This cable is used for networks longer than 100 m.

thin cable

The thin cable is specified in the physical layer definitions of the DeviceNet specification. This cable is used for drop lines and networks shorter than 100 m.

time message (TIME)

Standardized message in CANopen containing the time as a 6-byte value given in ms after midnight and days after 1st January 1984.

time quanta

Atomic time unit in a CAN network.

time stamp

Some CAN controllers provide the possibility of assigning time information to each received message. For TTCAN level 2 it is also required that the transmitting node captures the time and includes the time stamp in the data field of the very same frame.


Time-triggered messages are transmitted in pre-defined time slots. This requires a global time-synchronization and the avoidance of automatic retransmission of faulty messages. Time-triggered communication for CAN is standardized in ISO 11898-4 (TTCAN).


See type of services.


Physical connection structure of the network (e.g. line, ring, star, and tree topology).


See transmit PDO.

transmission buffer(s)

Local memory in the CAN controller, where the message to be transmitted is stored.

transmission request

Internal event in the CAN controller to transmit a message.

transmission time capture

In TTCAN level 2 it is required to capture the time when the SOF bit of the reference message has been transmitted.

transmission type

CAN open object defining the scheduling of a CANopen communication object such as e.g. PDO.

transmit error counter (TEC)

CAN controller internal counter for transmission errors. The TEC value is readable in some controllers.

transmit PDO (TPDO)

A process data object that is transmitted by a CANopen device.


A node from which a data or remote frame (only in Classical CAN) originates. This node remains transmitter until the bus is idle again or until the node loses arbitration.

transmitter delay (TD)

Delay from the CAN FD controller's transmit flip-flop (FF) to its receive flip­ flop. When the CAN FD controller sends a bit, this bit appears at the CAN FD controller's receive pin after TD. TD includes the micro-controller internal delay, the transceiver delay and the delay on the ECU. This term is defined in ISO 11898-1. In CiA 601-1 the term transmitting node delay has the same meaning.

transmitter delay compensation (TDC)

At bit-rates higher than 1 Mbit/s in the data phase of CAN FD frames the transmitting node has to compensate the TD when comparing its transmitted bits to the delayed received bits. TDC mechanism defines a secondary sample point SSP. When it is used, the transmitter ignores bit errors detected at the (first) sample point. The received bit value is compared at the SSP, with the (delayed) transmitted bit value. If a bit error is detected at the SSP, the transmitter reacts to this bit error at the subsequent following sample point. Bit error detection is disabled for those bits at the end of the data phase where the SSPs of the bits would be in the following arbitration phase. This term is defined in ISO 11898-1. In CiA 601-1 the term transmitting node delay compensation is used to avoid misinterpretations as the transceivers discussed there have a transmitter part.

transmitting node delay

See transmitter delay.

transmitting node delay compensation

See transmitter delay compensation.

tree topology

Network topology with a trunk line and branch lines. The not terminated branches may cause reflections, which shall not exceed a critical value.


This value includes the propagation segment as well as the Phase_Seg 1 of a bit time.


This value is the same as the Phase_Seg 2 of a bit time.

TTC Time Triggered CAN

Standard CAN with extensions to support a global clock and scheduled transmission of messages in a system.

TTCAN protocol

Higher-layer protocol defining time­ triggered communication in CAN-based networks. The CAN controllers have to be capable of switching-off automatic retransmission of faulty messages and may be able to capture a 16-bit timer value at SOF transmission in order to transmit the timer value in the very same message. It is standardized in ISO 11898-4.

type of services (TOG)

As defined in CiA 602-2, the 3-bit TOC field of a C-PDU indicates whether it is a J1939 mapping C-PDU or a padding C-PDU.

Source CANdictionary (2016) - CiA CAN in Automation -