DSN - Defense Switched Network (formerly Automatic Voice Network or
Autovon); basic general-purpose, switched voice network of the Defense
Communications System (US Department of Defense).

Eutelsat - European Telecommunications Satellite Organization (Paris). Fiber-optic cable - a multichannel communications cable using a thread of optical glass fibers as a transmission medium in which the signal (voice, video, etc.) is in the form of a coded pulse of light.

GSM - a global system for mobile (cellular) communications devised by the Groupe Special Mobile of the pan-European standardization organization, Conference Europeanne des Posts et Telecommunications (CEPT) in 1982.

HF - high frequency; any radio frequency in the 3,000- to 30,000-kHz range.

Inmarsat - International Maritime Satellite Organization (London); provider of global mobile satellite communications for commercial, distress, and safety applications at sea, in the air, and on land.

Intelsat - International Telecommunications Satellite Organization
(Washington, DC).

Intersputnik - International Organization of Space Communications
(Moscow); first established in the former Soviet Union and the East
European countries, it is now marketing its services worldwide with
earth stations in North America, Africa, and East Asia.

Landline - communication wire or cable of any sort that is installed on poles or buried in the ground.

Marecs - Maritime European Communications Satellite used in the
Inmarsat system on lease from the European Space Agency.

Marisat - satellites of the Comsat Corporation that participate in the
Inmarsat system.