common-telephone network
31Integrated Services Digital Network — ISDN redirects here. For other uses, see ISDN (disambiguation). Integrated Services Digital Network (ISDN) is a set of communications standards for simultaneous digital transmission of voice, video, data, and other network services over the… …
32Business telephone system — Early model 464G Western Electric key telephone set A business telephone system is any of a range of a multiline telephone systems typically used in business environments, encompassing systems ranging from small key systems to large scale private …
33Public land mobile network — In telecommunication, a public land mobile network (PLMN) is a network that is established and operated by an administration or by a recognized operating agency (ROA) for the specific purpose of providing land mobile telecommunications services… …
34History of the telephone — The history of the telephone chronicles the development of electrical technology that enabled bidirectional human speech conversations over distances farther than a person could shout.Telephone prehistoryMechanical devicesBefore the invention of… …
35Mobile radio telephone — systems preceded modern cellular mobile telephony technology. Since they were the predecessors of the first generation of cellular telephones, these systems are sometimes retroactively referred to as pre cellular (or sometimes zero generation)… …
36American Telephone & Telegraph — For other companies with similar names, see AT T (disambiguation). Infobox Company company name = AT T Corporation company logo = type = Private (Subsidiary of AT T Inc.) foundation = 1885 location = Bedminster, New Jersey, United States industry …
37Cellular network — Top of a cellular radio tower A cellular network is a radio network distributed over land areas called cells, each served by at least one fixed location transceiver known as a cell site or base station. When joined together these cells provide… …
38Packet switched network — A Packet Switched Network, or PSN, refers to the packet switched networks that existed before the Internet. The history of such networks can be divided into three eras:early networks before the introduction of X.25 and OSI,the X.25 era when many… …
39Toll-free telephone number — A toll free, Freecall, Freephone, or 800 number is a special telephone number, in that the called party is charged the cost of the calls by the telephone carrier, instead of the calling party. The cost of the call to the called party is usually… …
40Class 4 telephone switch — A Class 4, or Tandem, telephone switch is a U.S. telephone company central office telephone exchange used to interconnect local exchange carrier offices for long distance communications in the Public Switched Telephone Network. A Class 4 switch… …
