25.		Terms and definitions abbreviations and acronyms : recommendations on means of expression (series B): general telecommunications statistics (series C) / International Telecommunication Union Data Publicação: 1989 Tema: Vária
26.		Line transmission of non-telephone signals : transmission of sound-programme and television signals: series H and J recommendations / International Telecommunication Union Data Publicação: 1989 Tema: Vária
27.		Telegraph transmission : series R recommendations Data Publicação: 1989 Tema: Vária
28.		Annuaire statistique des télécommunications du secteur public : (séries chronologiques 1978-1987) / Union Internationale des Télécommunications Data Publicação: 1989 Tema: UIT-União Internacional das Telecomunicações
29.		Specifications of signalling systems No. 6 : recommendations Q.251 - Q.300 / International Telecommunication Union Data Publicação: 1989 Tema: Vária
30.		Terminal equipment and protocols for telematic services : recommendations T.400 - T.418 / International Telecommunication Union Data Publicação: 1989 Tema: Vária
31.		General recommendations on telephone switching and signalling : functions and information flows for service in the ISDN: supplements: recommendations Q.1- Q.118 bis / International Telecommunication Union Data Publicação: 1989 Tema: Vária
32.		International analogue carrier systems : recommendations G.211 - G.544 / International Telecommunication Union Data Publicação: 1989 Tema: Vária
33.		Telematic, data transmission and teleconference services operations and quality of service : recommendations F.160 - F.353, F.600, F.601, F.710 - F.730 / International Telecommunication Union Data Publicação: 1989 Tema: Vária
34.		Data communication networks : interworking between networks, mobile data transmission systems, internetwork management: recommendations X.300 - X.370 /International Telecommunication Union Data Publicação: 1989 Tema: Vária
35.		Annex F.2 to recommendation Z.100 : SDL formal definition: static semantics/International Telecommunication Union Data Publicação: 1989 Tema: Vária
36.		Integrated services digital network (ISDN) : overall network aspects and functions, ISDN user-network interfaces: recommendations I.310 - I.470 / International Telecommunication Union Data Publicação: 1989 Tema: Vária