Talk:ISO 15765-2

This is hopefully a completely non-controversial topic, with few attempts to inject product advertisements as has happened with other OBD-2 topics.

The only likely objection is one that has repeatedly caused deletions and reversions in other OBD-2 topics: a claim that it is somehow illegal or a copyright violation to publish a description of the standards. As has been repeated many times, a non-verbatim description is not a violation of any rights. Not copyright, nor any stretch of trademark law. And a standard certainly isn't a trade secret.

This page started out as a mechanical translation from a German language placeholder. Donald Becker edited, and eventually completely rewrote it using open documents and observation of implementations. It was later reviewed and slightly corrected based on the standard document itself.

clarify KWP2000 vs CAN vs OBD vs ISO-TP contradiction
This article states that ISO-TP is a protocol for sending larger messages over the CAN bus (by splitting a packet into multiple frames, since CAN only supports 8-byte message frames). But confusingly this article also says ISO-TP is primarily used for KWP2000, whereas the KWP2000 article says that KWP2000 is completely separate from CAN (using physically separate hardware connections and an unrelated protocol). I think a number of concepts been to be clarified and distinguished correctly. Is the following correct:


 * CAN: a pair of conductors ("high" and "low" line), differential signalling, priority arbitration strategy (many transmitting nodes can compete without collision), max 8 bytes per message. Used constantly for normal operation of a car (communication between numerous control units, sensors and actuators, throughout engine and body).
 * KWP2000: single conductor ("K-line"), UART signalling, request-wait-responses protocol, messages up to 255 bytes. Used for technician to communicate with ECUs.
 * ISO-TP: 4kb messages over CAN system. Used for??
 * OBD connector: a physical point for a technician to patch into e.g. both CAN lines and K-line.
 * (E)OBD2: specification for communicating only some general diagnostic information via the lower layers presented at OBD connector??
 * ELM327: higher level serial interface (not requiring the precise timing of the lower layers) for basic subset of (E)OBD2 ?? Similar to J2534 ??
 * UDS: relates how exactly?

Does the article mean that the most common application of ISO-TP is that some ECUs respond to requests over CAN bus that would normally only be sent on the K-line? Or is ISO-TP also used to split larger messages over the K-line itself? Cesiumfrog (talk) 04:31, 12 November 2017 (UTC)

Extended Addressing
In a scenario where two CAN nodes A and B are talking to each other, if node A uses Extended Addressing in its frames is it safe to assume that node B will, too? Also, what indicates that a frame uses Extended Addressing at all? How is a node able to distinguish the Extended Addressing byte from a regular data byte? Antred (talk) 00:00, 16 March 2019 (UTC)

CAN FD vs CAN
How CAN FD and CAN relates to this protocol and are there any difference in the PCI/Flow controls etc? — Preceding unsigned comment added by Digiajay (talk • contribs) 16:18, 6 July 2020 (UTC)