Publicly Available Telephone Services

Publicly Available Telephone Services (PATS) means a service available to the public for originating and receiving national and international calls and access to emergency services through a telephone number or numbers in a national or international telephone numbering plan, and may, where relevant, also include one or more of the following: (a) operator assistance, (b) directory assistance facilities, (c) directories, (d) pay telephones, (e) service under special terms, (f) specific facilities for end-users with a disability or with special social needs, and (g) non-geographic services == Resilience == A plain old telephone service has high reliability and is unlikely to be affected by local power outages. More modern systems require battery back-up to guard against local power outages.

Source: Wikipedia — Publicly Available Telephone Services (CC BY-SA 4.0)