Integrated Services Digital Network (ISDN); Conference call, add-on (CONF) supplementary service; Digital Subscriber Signalling System No. one (DSS1) protocol; Part 5: Test Suite Structure and Test Purposes (TSS&TP) specification for the network
Universal Mobile Telecommunications System (UMTS); Requirements on User Equipments (UEs) supporting a release-independent frequency band (3GPP TS 25.307 version 16.0.0 Release 16)
Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); LTE; Service accessibility (3GPP TS 22.011 version 16.5.0 Release 16)
Universal Mobile Telecommunications System (UMTS); LTE; IP multimedia call control protocol based on SIP and SDP; User Equipment (UE) conformance specification; Part 2: Implementation Conformance Statement (ICS) specification (3GPP TS 34.229-2 version 15.5.0 Release 15)