AS/NZS 4157.2:1994

This part of ISO/IEC 8882 defines an abstract test suite for testing the conformance of the Data Link Layer of an IUT with respect to ISO 7776 or the CCITT Recommendation X.25 (1980, 1984).Conformance of a Data Terminal Equipment (DTE) to the above ISO International Standard or CCITT Recommendations is tested using a dedicated circuit between the tester and the DTE. It is noted that CCITT Recommendations X.25-1980 and X.25-1984 are written from the perspective of a DCE and therefore do not always explicitly specify the DTE's operation. In such cases it is assumed that recommended operation of a DTE is included by implication because of the need to communicate with X.25 DCEs. This part of ISO/IEC 8882 excludes the testing of the LAP procedures given in the CCITT Recommendations.Note: Test cases for extended mode operation (Modulo 128), multilink procedure and DTE-DTE operation as per ISO 7776 are for further study.The tests in this part of ISO/IEC 8882 are designed for three possible interworking situations, shown in Figure 1. This part specifies tests for all three cases shown in Figure 1, but recognizes that not every test may apply to a particular DTE. A test selection procedure has to be performed to determine the applicability of a test to a particular DTE. Such selection will be based on the PICS and the PIXIT.In the rest of this part of ISO/IEC 8882, the term "X.25 standards" shall mean all three of CCITT Recommendation X.25(1980), CCITT Recommendation X.25(1984), and ISO/IEC 7776 International Standard, unless stated otherwise.

Under Revision see DR 99244 CP First published as Joint Standard AS/NZS 4157.2:1994.