"General: This test plan defines the test requirements for determining that Bus Interface Units (BIUs) meet the requirements of SAE AS4074@ Linear Token Passing Multiplex Data Bus. Application: This is a general test plan that completely describes the validation testing of and BIUs designed to meet the requirements of AS4074. The task group recognizes that a complete validation test of a BIU for AS4074 will be a lengthy and costly process. However@ from a technical viewpoint@ a complete validation test should be accomplished during the design verification process. Decisions to deviate from this test plan because of programmatic of financial concerns are not within the purview of the technical community@ and may ultimately be made on other than technical grounds. The primary intent of this plan is to test those requirements of AS4074 for BIUs that have been implemented in hardware@ software or firmware. However@ it is recognized that some additional software may be required to meet this intent and that this software may be the operational software (or some portion thereof)@ special test software or some combination of these. This document deals only with BIU functions which are explicitly specified in AS4074. This document does not specify tests that check the integrity of data from the Host to the bus@ nor does it attempt to address the system test requirements. For production-level testing@ the task group is developing a companion document@ AIR4753@ ""Acceptance Test Plan for AS4074@ Linear Token Passing Multiplex Data Bus."" This document suggests a subset of the tests defined to be performed on each BIU as a production acceptance test."