ISO 16844-4-2022 PDF

Full title and description

Road vehicles — Tachograph systems — Part 4: Display unit communication interface. This international standard specifies the CAN-based data communication between a tachograph display unit and other devices on an SAE J1939-based in-vehicle network, covering physical, data link, network and application layers and defining supported parameter groups and message behaviours.

Abstract

Specifies CAN-based data communication for tachograph display units on SAE J1939 in-vehicle networks. Requirements and recommendations are provided across OSI layers (physical, data link, network, application); the document also lists parameter groups and mandatory/optional messages used for exchanging tachograph-related data.

General information

• Status: Published.
• Publication date: 25 February 2022 (Edition 3 / 2022‑02).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 43.040.10 — Electrical and electronic equipment (road vehicles).
• Edition / version: Edition 3 (2022).
• Number of pages: 12 pages.

Scope

Defines the CAN-based communication interface between a tachograph display unit and other vehicle devices on an SAE J1939 in-vehicle network. The scope covers requirements and recommendations for the physical, data link, network and application layers (OSI model) and specifies the parameter groups and message formats used for tachograph data exchange. It is intended to ensure interoperable, reliable exchange of tachograph-related information over CAN/J1939.

Key topics and requirements

• CAN communication over an SAE J1939-based in-vehicle network (message and parameter group definitions for display unit interaction).
• Physical- and data-link-layer requirements (conformance with ISO 11898-1 and J1939 framing rules; support for specified bit timings and single-sample timing windows for 250 kbit/s and 500 kbit/s operation).
• Use of Classical Extended Frame Format (CEFF) frames and prohibition of remote frames; transport-layer support for J1939 transport protocols (BAM, TP.DT) for multi-frame transfers.
• Application-layer conventions based on SAE J1939-21 and J1939-71, including mandatory and optional parameter groups and encoding rules (byte order, ASCII string order, control/acknowledgement semantics).
• Lists of mandatory messages (example: time/date, vehicle identification, high-resolution vehicle distance, service/reset/tachograph messages, driver identification) and optional PGs; guidance on message handling and acknowledgements.

Typical use and users

Manufacturers of tachographs and vehicle electronic control units (ECUs), in‑vehicle network designers, automotive software developers, testing and certification bodies, fleet operators and regulatory authorities implementing or verifying tachograph interfaces and interoperability on CAN/J1939 networks. The standard is used when designing or specifying the display-unit communications portion of tachograph systems.

Related standards

Part of the ISO 16844 series (tachograph systems). Closely related parts include ISO 16844-1 (electromechanical components / electrical connectors), ISO 16844-6 (diagnostic communication interfaces) and ISO 16844-7 (parameters), among others; earlier editions (for example ISO 16844-4:2015) were withdrawn and replaced by the 2022 edition. The series is maintained by ISO/TC 22/SC 31.

Keywords

tachograph, CAN, SAE J1939, display unit, in‑vehicle network, parameter groups, transport protocol, ISO 16844, vehicle communications, ECU, data link, OSI layers.

FAQ

Q: What is this standard?

A: ISO 16844-4:2022 specifies the display‑unit communication interface for tachograph systems — i.e., the CAN/J1939‑based messaging, parameter groups and related requirements used to exchange tachograph data between a display unit and other vehicle devices.

Q: What does it cover?

A: It covers physical, data link, network and application layer requirements for CAN communication on an SAE J1939 in‑vehicle network, message/parameter group definitions, transport behaviours for multi‑frame messages and encoding/acknowledgement rules.

Q: Who typically uses it?

A: Tachograph manufacturers, vehicle OEM engineers, ECU and network suppliers, test houses, certification bodies, fleet technology integrators and regulators who need a consistent, interoperable interface for tachograph display communications.

Q: Is it current or superseded?

A: The document was published as Edition 3 in February 2022 and is the current published version (replacing the 2015 edition). ISO records indicate the standard is in the published lifecycle stage and listed with a review/revision status (scheduled review/revision activity noted in ISO metadata). A committee draft to revise the part has been recorded as under development (i.e., future revision work may be underway).

Q: Is it part of a series?

A: Yes — ISO 16844 is a multi‑part series addressing tachograph systems (electromechanical components, interfaces, CAN/K‑line diagnostics, parameters, etc.). ISO/TC 22/SC 31 is the technical committee responsible for the series.

Q: What are the key keywords?

A: Key keywords include: tachograph, CAN, SAE J1939, display unit, in‑vehicle network, parameter group (PG), transport protocol (BAM/TP.DT), ISO 16844.