TELEPHONIC COMMUNICATION

**Definition:** This place covers:

**Limiting references (this place does not cover):** - Circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus -> G08

**Glossary:** - Exchange: Synonym for telephone switch. - Satellite: A kind of exchange the operation of which depends upon control signals received from a supervisory exchange. - Subscriber: General term for a user of terminal equipment, e.g. for the user of a telephone set, or for any equipment used by subscribers, e.g. telephones for public use. - Substation: Subscriber or monitoring equipment which may connect a single subscriber to a line without choice as to subscriber. - Switching centres: Include exchanges and satellites. - Voice mail system: A centralized system for managing telephone messages for a large group of users.