Purpose
In basic telephony there are two types of offices: local and foreign. A local office was assigned a specific area, and all telephone services provided to that area came from that central office. Each central office had its unique identifier. In the early days names were used, such as "Jackson" or "Newton". The office names were changed to three-digit numerical exchange codes (NNX), prefixed to the local phone number (not the area code).
Customers who want a telephone number provided by a neighboring telephone central office, lease a "foreign exchange" line. With the old two-wire loop technology, this would require an engineered circuit with increased costs. The practice is rare except in big cities.
Read more about this topic: Foreign Exchange Service (telecommunications)
Famous quotes containing the word purpose:
“I envy neither the heart nor the head of any legislator who has been born to an inheritance of privileges, who has behind him ages of education, dominion, civilization, and Christianity, if he stands opposed to the passage of a national education bill, whose purpose is to secure education to the children of those who were born under the shadow of institutions which made it a crime to read.”
—Frances Ellen Watkins Harper (1825–1911)
“The purpose of playing, whose end, both at the first and now,
was and is, to hold as ‘twere the mirror up to nature: to show
virtue her feature, scorn her own image, and the very age and
body of the time his form and pressure.”
—William Shakespeare (1564–1616)
“I don’t like to be idle; in fact, I often feel somewhat guilty unless there is some purpose to what I am doing. But spending a few hours—or a few days—in the woods, swamps or alongside a stream has never seemed to me a waste of time.... I derive special benefit from a period of solitude.”
—Jimmy Carter (James Earl Carter, Jr.)