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

V interfaces at the digital Local Exchange (LE) - V5.1 interface for the support of Access Network (AN) - Part 7: Test Suite Structure and Test Purposes (TSS&TP) specification for the data link layer as German standard) (Endorsement of the English version ETS 300324-7:1999 as German standard)
Edition 2000-10

V interfaces at the digital Local Exchange (LE) - V5.2 interface for the support of Access Network (AN) - Part 7: Test Suite Structure and Test Purposes (TSS&TP) specification for the data link layer (Endorsement of the English version ETS 300347-7:1999 as German standard)
Edition 2000-10

Integrated Services Digital Network (ISDN) - Digital Subscriber Signalling System No. one (DSS1) protocol - Data link layer - Part 1: General aspects [ITU-T Q.920 (1993), modified]; English version ETS 300402-1:1995
Edition 1996-06

Integrated Services Digital Network (ISDN) - Digital Subscriber Signalling System No. one (DSS1) protocol - Data link layer - Part 2: General protocol specification [ITU-T Q.921 (1993), modified]; English version ETS 300402-2:1995
Edition 1996-06

Integrated Services Digital Network (ISDN) - Digital Subscriber Signalling System No. one (DSS1) protocol - Data link layer - Part 3: Frame relay protocol specification; English version ETS 300402-3:1996
Edition 1997-04

Integrated Services Digital Network (ISDN) - Digital Subscriber Signalling System No. one (DSS1) protocol - Data link layer - Part 5: Protocol Implementation Conformance Statement (PICS) proforma specification for the frame relay protocol; English version ETS 300402-5:1996
Edition 1997-04

Integrated Services Digital Network (ISDN) - Digital Subscriber Signalling System No. one (DSS1) protocol - Data link layer - Part 6: Test Suite Structure and Test Purposes (TSS&TP) specification for the general protocol; English version ETS 300402-6:1997
Edition 1997-11

Private Integrated Services Network (PISN) - Inter-exchange signalling protocol, Circuit mode basic services, Data Link Layer (DLL) - Part 1: Test Suite Structure and Test Purposes (TSS&TP); English version ETS 300804-1:1998
Edition 1998-12

Private Integrated Services Network (PISN) - Inter-exchange signalling protocol, Circuit mode basic services, Data Link Layer (DLL) - Part 2: Abstract Test Suite (ATS) specification; English version ETS 300804-2:1998
Edition 1998-12