for Testing (PIXIT) proforma for the user-network interface data link layer PSTN-GW part at the T* or V1* reference
points shown in figure 2 of EN 301 141-1 [1]. The present document contains the ATS and partial PIXIT proforma for
only the NTN side.
EN 301 141-2 [2] specifies the Protocol Implementation Conformance Statement (PICS) proforma related to this ATS.
EN 301 141-3 [3] specifies the Test Suite Structure and Test Purposes (TSS&TP) related to this ATS and partial PIXIT
proforma specification.
An NMDS implementation may contain one ISDN-BA port and/or a limited number of PSTN ports up to a maximum
of 10. Typically one or two PSTN ports would be supported.
The objective of the present document part is to provide conformance tests giving a high probability of inter-operability
of a Network Termination Node (NTN) and a Local Exchange (LE) on the DLL from different manufacturers over the
NMDS interface. The present document covers only the procedures described in EN 301 141-1 [1].
ISO/IEC 9646-1 [11] is used as the basis for the methodology of conformance testing.
EN 301 141-1 [1] defines the NMDS layer 2 functions:
For the ISDN-BA layer 2 functions, point-to-point (i.e. TEI 0) or point-to-multipoint procedures may be
supported using the full ISDN TEI assignment procedures as currently defined. These include TEI assignment
and removal procedures. However, there is an NMDS-specific constraint. TEI values 117 through 126 are now
reserved for the PSTN_GW layer 2 frames and shall not be used for the ISDN_BA frames. Thus, the DLL TSS
and TP as given in ETS 300 402-6 [6] apply as well to the NMDS interface for the ISDN-BA layer 2. The
present document does not repeat them.
For the PSTN layer 2 functions, EN 301 141-1 [1] presents two different state machines. The NTN DLL state
machine is an adaptation of the ISDN DSS1 protocol data link layer in ETS 300 402-2 [5]. The LE layer 2 state
machine shall b (...abbreviated)