Apparatus for connection to private circuits run by certain public telecommunication operators, Specification for apparatus for connection to direct current circuits— 24 стр.
Specification for general requirements for apparatus for connection to public switched telephone networks run by certain public telecommunication operators— 44 стр.
Glossary of electrotechnical, power, telecommunication, electronics, lighting and colour terms. Terms particular to telecommunications and electronics, Telephony— 138 стр.
Glossary of electrotechnical, power, telecommunication, electronics, lighting and colour terms. Terms common to power, telecommunications and electronics, Fundamental terminology— 52 стр.