АТС(In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls. A central office (CO) is the physical building used to house inside plant equipment including telephone switches, which make telephone calls "work" in the sense of making connections and relaying the speech information. wiki Alexander Demidov)
телефонная розетка(Telephone jacks are sockets that receive telephone plugs. A telephone jack is usually wired to a telephone line in a building, which usually corresponds to a single telephone number. wiki Alexander Demidov)