This protocol covers the application layer in the OSI model of computer networking.
One underlying physical layer used for KWP2000 is identical to ISO 9141, with bidirectional serial communication on a single line called the K-line.
KWP2000 is also compatible on ISO 11898 (Controller Area Network) supporting higher data rates of up to 1 Mbit/s.
CAN is becoming an increasingly popular alternative to K-line because the CAN bus is usually present in modern-day vehicles and thus removing the need to install an additional physical cable.
ISO 14230 Road vehicles – Diagnostic systems – Keyword Protocol 2000 is structured as follows: