ry code in
brackets, the city or area code (where required) in parentheses, and
the local number. The one component that is not presented is the
international access code, which varies from country to country. For
example, an international direct dial telephone call placed from the US
to Madrid, Spain, would be as follows:

011 [34] (1) 577-xxxx, where
011 is the international access code for station-to-station calls;
01 is for calls other than station-to-station calls,
[34] is the country code for Spain,
(1) is the city code for Madrid,
577 is the local exchange, and
xxxx is the local telephone number.

An international direct dial telephone call placed from another country
to the US would be as follows:
international access code + [1] (202) 939-xxxx, where
[1] is the country code for the US,
(202) is the area code for Washington, DC,
939 is the local exchange, and
xxxx is the local telephone number.

Telephone system
This entry includes a brief general assessment of the system with
details on the domestic and international components. The following
terms and abbreviations are used throughout the entry:

Africa ONE - a fiber-optic submarine cable link encircling the
continent of Africa.
Arabsat - Arab Satellite Communications Organization (Riyadh,
Saudi Arabia).
Autodin - Automatic Digital Network (US Department of Defense).
CB - citizen's band mobile radio communications.
cellular telephone system - the telephones in this system are
radio transceivers, with each instrument having its own private radio
frequency and sufficient radiated power to reach the booster station in
its area (cell), from which the telephone signal is fed to a telephone
exchange.
Central American Microwave System - a trunk microwave radio relay
system that links the countries of Central America and Mexico with each
other.
coaxial cable - a multichannel communication cable consisting of a
central conducting wire, surrounded by and insulated from a cylindrical
conducting shell; a large number of telephone channels can be made
available within the insulated space by the use of a large number of
carrier frequencies.
Comsat - Communications Satellite Corporation (US).
DSN - Defense Switched Network (formerly Automatic Voice Network
or Autovon); basic general-purpose, switched voice network of the
Defense Communications System (US Department