European digital cellular telecommunications system (Phase 2) - Mobile Station - Base Station System (MS-BSS) interface - Data Link (DL) layer specification; English version ETS 300555:1994
Edition 1995-01

Private Integrated Services Network (PISN) - Inter-exchange signalling protocol, Generic functional protocol for the support of supplementary services - Part 2: Abstract Test Suite (ATS) specification; English version ETS 300806-2:1998
Edition 1998-12

Integrated Services Digital Network (ISDN); user-network interface data link layer specification; application of CCITT recommendations Q.920/I.440 and Q.921/I.441; english version ETS 300125:1991
Edition 1992-05

Integrated Services Digital Network (ISDN) - Digital Subscriber Signalling System No. one (DSS1) protocol - Signalling network layer for circuit-mode basic call control - Part 4: Test Suite Structure and Test Purposes (TSS&TP) specification for the user; English version ETS 300403-4:1997
Edition 1997-11

Private Telecommunication Network (PTN); signalling protocol at the S-reference point; circuit mode basic services; English version ETS 300192:1992
Edition 1993-09