Integrated Services Digital Network (ISDN);Subaddressing (SUB) supplementary service;Digital Subscriber Signalling System No. one (DSS1) protocol;Part 3: Test Suite Structure and Test Purposes (TSS&TP) specification for the user (Endorsed by Asociación Española de Normalización in February of 2022.)
Integrated Services Digital Network (ISDN);Subaddressing (SUB) supplementary service;Digital Subscriber Signalling System No. one (DSS1) protocol;Part 3: Test Suite Structure and Test Purposes (TSS&TP) specification for the user (Endorsed by Asociación Española de Normalización in February of 2022.)
