AD HOC: Industry term for on-demand verses full-time services.

AMPLIFIER: A device used to increase the strength of electrical signals.

ANALOG: A form of transmitting information characterized by continuous and variable signal levels. Off-air broadcast TV is an example of analog signals.

ANTENNA: The device that sends and/or receives signals from the satellite. Also referred to as a satellite dish.

APERTURE: A cross-sectional area of the antenna actually exposed to the satellite signals.

APOGEE: The highest point in the satellite's orbit. See perigee.

ARF: Alternate Recovery Facility. The backup station for satellite control.

ARIANESPACE: One of PanAmSat's major launch vehicle suppliers that launches rockets out of a space center in French Guiana, Kourou.

ASYMMETRIC CIRCUIT: A two-way satellite link with inbound and outbound paths set at different rates.

ATTITUDE CONTROL: Maintenance of the satellite's orientation with respect to the earth and the sun.

AZIMUTH: The horizontal angle between true north and an antenna pointing, with true north set to 0.0 degrees, and due south set to 180 degrees.

BACKHAUL SERVICES: See contribution.

BANDWIDTH: The amount of spectrum a communication channel (analog or digital) uses, measured in hertz (Hz).

BEAMWIDTH: A measure for the pointing accuracy of a satellite antenna, in degrees. Large antennas have smaller beamwidths, while smaller antennas have larger beamwidths.

BIRD: A nickname for a satellite.

BIT: A single unit of information in the binary system which takes on the value of 1 or 0.

BOEING SATELLITE SYSTEMS (BSS): Satellite manufacturer previously owned by Hughes Electronics and named Hughes Space and Communications Co. BSS manufactures the Boeing 601, Boeing 601 HP and Boeing 702 model satellites.

Boeing 601: Boeing-built body-stabilized spacecraft model used for high power payloads, including direct broadcast and mobile communications applications.

Boeing 601 HP: A higher-powered version of the HS 601 model satellite built by Boeing Satellite Systems.

Boeing 702: The Newest Boeing-built body-stabilized spacecraft with nearly twice the capacity and double the power of a Boeing 601 HP satellite, used for multiple payloads. GXI is a Boeing 702 spacecraft.

BROADBAND: A term used to refer to high-speed communication networks that are designed to handle bandwidth-intensive applications.

BROADCASTING: To transmit a signal to multiple locations simultaneously over satellite, radio/TV station, data communications network or e-mail system.

BUS: The area of the satellite with components for support tracking, telemetry and command (TT&C), power systems, propulsion and control of the spacecraft.

CARRIER: 1) A telephone long distance company that operates fiber/satellite/microwave networks to carry voice and data traffic. A local exchange carrier (LEC) is a local phone company and an inter-exchange carrier (IEC or IXC) carries long-distance calls. 2) A continuous radio frequency (RF) signal used to carry another information signal.

CACHE: A place to store something temporarily. Web pages you request are stored in your browser's cache directory on your hard disk. When you return to a page you've recently viewed, the browser gets it from the cache rather than the original server, saving you time and the network additional traffic. You can usually vary the size of your cache, depending on your particular browser.

CACHE SERVER: A server relatively close to Internet users and typically within a business enterprise that saves (caches) Web pages and possibly FTP and other files that all users have requested. Successive requests for these pages or files can be satisfied by the cache server rather than the Internet. A cache server not only gets information more quickly but also reduces Internet traffic.

C-BAND: Refers to the frequency in the 3.4 GHz to 7 GHz range. Portions of this band are dedicated to satellite communications. Satellite downlinks are 3.7 to 4.2 GHz.

CDV: Compressed Digital Video. A compression technique used in satellite broadcast systems that reduces the amount of bandwidth needed to transmit video.

CHANNEL: Path for electrical communication between two facilities. Also called a circuit, link or path.

CIRCUIT: A satellite link. See channel.

CIRCULAR POLARIZATION: A mode of transmission in which signals are downlinked in a rotating corkscrew pattern.

CMS: Carrier Monitoring System. A monitoring system that measures uplink and downlink signal performance on PanAmSat satellites.

CO-LOCATION: Placement of more than one satellite at the same orbital location. From the ground, they appear as one satellite that can receive with a single antenna, provided they use the same frequency band.

COMMON CARRIER: A company that owns a transmission medium and leases or sells portions of the medium for a set tariff. AT&T, MCI/WorldCom and Sprint are common carriers. See carrier.

COMPRESSION: Reducing the amount of bandwidth needed to transmit video or audio by digitizing an analog signal, thus increasing the ability to load multiple services on a satellite transponder.

CONTRIBUTION SERVICES: Also referred to as backhaul. Capacity used to consolidate programming from various locations and assemble them in one central location for the final programming product. The final outbound channel would be considered distribution. This can apply to satellite news gathering or program syndication services.

CONUS: Continental United States. A term used to describe satellite coverage limited to the continental United States.

DAMA: Demand Assigned Multiple Access. A bandwidth-sharing scheme allowing multiple users to share a pool of frequencies or channels on demand. A central hub manages the usage of the bandwidth. This technology is mainly used for rural telephony.

DBS: Direct Broadcast Satellite. A service that uses satellites to broadcast multiple channels of television programming directly to small dish antennas.

DECODER: A device used to unscramble encrypted or "scrambled" television signals.

DELAY: The time it takes for a signal to travel from a transmitting earth station, through space, to a satellite and back. This time calculates to be about ¼ of a second.

DIGITAL: A quantification scheme that allows the conversion of analog information into bits of data. Digitization allows for signal compression and for maintaining signal integrity.

DIGITAL DATA COMPRESSION: A process by which a complex set of algorithms are employed to rearrange, reassemble and eliminate digital information from data inventory, so the amount of data transported is reduced without noticeable loss of resolution or information.

DISH: See antenna or earth station.

DOA: Day of air.

DOWNLINK: The transmission of radio frequency signals from a satellite to an earth station.

DSL: Digital Subscriber Line. A technology for bringing high-bandwidth information to homes and small businesses over ordinary copper telephone lines. A home or small business close enough to a telephone company central office that offers DSL may be able to receive data at rates up to 6.1 megabits (millions of bits) per second. This enables continuous transmission of motion video, audio, and even 3-D effects. More typically, individual connections will provide from 512 kbps to 1.544 Mbps downstream and about 128 kbps upstream. A DSL line can carry both data and voice signals, and the data part of the line is continuously connected.

DSS: Digital satellite system.

DTH: Direct-to-Home Television. A satellite service that delivers television programming direct to consumer's homes using a small antenna and related equipment. Satellites that provide DTH services are specialized to operate in a different frequency to allow for very small dishes. PanAmSat satellites serve as platforms for current and planned DTH television services in Latin America, South America, Taiwan and the United States. See DBS.

DUPLEX: Method in which transmission is possible in both directions of a telecommunications channel. Simultaneous two-way operation is known as "full duplex". Operating in only one direction at a time is known as "half duplex" or "simplex."

EARTH STATION: A ground-based antenna and associated equipment used to receive and/or transmit telecommunications signals via satellite. See dish.

ECLIPSE: Occurs when a satellite passes through the line between the earth and the sun or the earth and another satellite, resulting in a service outage.

EIRP: Effective Isotropic Radiated Power. Refers to the measure of the satellite signal strength on the ground in reference to an isotropic source.

ELEVATION: The angle between an antenna beam and the horizontal plane.

ENCRYPTION: Process of electronically ciphering a signal so it cannot be received without a decoder.

FCC: Federal Communications Commission. The U.S. federal regulatory agency responsible for the regulation of interstate and international communications by radio, television, wire, satellite and cable.

FEEDS: Device mounted at the focal point of the antenna that gathers signals reflected from the dish. Also a television signal source.

FIBER: Fiber optic (or "optical fiber") refers to the medium and the technology associated with the transmission of information as light impulses travel along a glass or plastic wire or fiber. Fiber optic wire carries more information than conventional copper wire and is less subject to electromagnetic interference. Most telephone company long-distance lines are now fiber optic.

FOOTPRINT: The coverage area of the earth's surface within which the signals of a specific satellite can be received.

FREQUENCY: The rate at which a signal (e.g. electrical current) alternates. The standard unit of frequency is the hertz, abbreviated Hz. If a signal completes one cycle per second, then the frequency is 1 Hz; 60 cycles per second equals 60 Hz.

• Hz: Hertz. The name of the basic measure of frequency at which an electromagnetic wave completes a full cycle from its positive to its negative pole and back again. Each unit is equal to one cycle per second.

• KHz: Kilohertz. Refers to a unit of frequency equal to 1,000 Hertz.

• MHz: Megahertz. Refers to a frequency equal to one million Hertz.

• GHz: Gigahertz. Refers to a frequency equal to one billion Hertz.

FDMA: Frequency division multiple access. Refers to the use of multiple carriers within the same transponder where each uplink has an assigned frequency slot and bandwidth.

FULL-TIME PROGRAM DISTRIBUTION: PanAmSat's core service consisting of the distribution of video programming channels or services for reception at cable headends around the world for prime media companies including Disney, Viacom, News Corp and AOL Time Warner.

GALAXY: PanAmSat's brand name for domestic U.S. satellites.

GEOSYNCHRONOUS ORBIT: An orbit 22,300 miles above the earth's equator where satellites circle at the same rate as the earth's rotation.

GEOSTATIONARY SATELLITE: A satellite orbiting 36,000 kilometers (22,300 miles) directly over the earth's equator. From earth, a geostationary satellite always appears to be in the same location because it finishes one rotation around the earth in 24 hours. Fuel on board the satellite is used to perform the "station-keeping" function, which maintains the satellite within a prescribed location, or box.

GMT: Greenwich Mean Time. The time zone that includes Greenwich, England is bisected by zero degrees longitude. This is the time notation that is used for booking international satellite time.

GPS: Global Positioning System. A satellite system that provides precise reference to the location of a point on earth. GPS satellite systems employ lower orbiting satellites than geostationary satellite networks.

HDTV: High definition television. Offers approximately twice the vertical and horizontal resolution of current NTSC analog television broadcasting and supports sound quality approaching that of a CD.

HE: Hughes Electronics Corporation. HE is a wholly owned subsidiary of General Motors Corporation and as PanAmSat's parent company, owns 81% of PanAmSat stock. HE is a provider of digital television entertainment, and satellite and wireless systems and services.

HEADEND: Location where cable television systems collect and distribute satellite programming.

HNS: Hughes Network Systems, Inc. HNS is a division of Hughes Electronics Corporation that designs, manufactures and installs satellite-based advanced networking solutions for corporations and governments worldwide. HNS pioneered many of the technologies currently in use today, including Very Small Aperture Terminal (VSAT) satellite networks, high-capacity digital cellular and wireless, and commercial packet switching.

HOPS: The number of routers or gateways on any given path.

HUB: The point on a network where circuits are connected or a network operations center for very small aperture terminal (VSAT) operations.

HYBRID SATELLITE: A satellite that carries two or more different communications payloads (i.e. C-band and Ku-band).

IFRB: International Frequency Registration Board.

INCLINED ORBIT: A condition that occurs when a satellite is no longer station-kept in the north south plain. A satellite operator might do so to extend the life of a satellite because fuel will only be used to perform station-keeping in the east-west plain. The inclination happens gradually over time, and once it becomes excessive, the satellite is de-orbited.

INTERNET BACKBONE: The network spanning the world that is provided by a handful of national Internet Service Providers (ISPs). They use connections running at approximately 45 megabytes per second linked up at specified interconnection points called national access points. Local ISPs connect to this backbone through routers, so data can be carried through the backbone to its final destination.

INTERNET GATEWAYS: A network point that acts as an entrance to another network. On the Internet, a node or stopping point can be either a gateway node or a host (end-point) node. Both the computers of Internet users and the computers that serve pages to users are host nodes. The computers that control traffic within your company's network or at your local ISP are gateway nodes.

IP: Internet protocol (IP) is the method by which data is sent from one computer to another on the Internet. Each computer on the Internet has at least one IP address that uniquely identifies it from all other computers on the Internet. When you send or receive data (for example, an e-mail note or a Web page), the message gets divided into little chunks called packets. Each of these packets contains both the sender's Internet address and the receiver's address.

ISDN: Integrated services digital network. A standard for the integrated transmission of voice, video, and data developed by the Consultative Committee on International Telephony and Telegraphy (CCITT).

ISO: ISO (International Organization for Standardization), founded in 1947, is a worldwide federation of national standards bodies from some 100 countries, one from each country. "ISO" is not an abbreviation. It is a word, derived from the Greek isos, meaning "equal." The name ISO is used around the world to denote the organization, thus avoiding the assortment of abbreviations that would result from the translation of "International Organization for Standardization" into the different national languages of members.

ISP: Internet Service Provider. A vendor who provides access for customers (companies and private individuals) to the Internet and the World Wide Web. Users typically reach their ISP by modem and phone line.

IT: Information technology. All equipment, processes, procedures and systems within an organization and those reaching out to customers and suppliers.

ITAR: International traffic in arms regulations. U.S. export laws under the State Department regulating the disclosure and dissemination of technical information to foreign persons.

ITU: International Telecommunications Union. The international regulatory authority that determines and mediates which countries and companies have rights to orbital slots.

JAMMING: Deliberate interference with a signal caused by another signal transmitted in the same frequency.

JPEG: Joint pictures expert group. A subgroup of ISO, which has established international standards for the digital compression of still pictures.

Ka-BAND: Primarily used in satellites operating at 30GHz uplink and 20 GHz downlink and is intended in support of future applications such as mobile voice. A portion of the RF spectrum located between 18 GHz and 31 GHz.

Ku-BAND: Refers to the frequency in the 12 GHz to 14 GHz range used in support of such applications as broadcast TV, DBS, and direct-to-home television.

LAN: Local Area Network. A local area network (LAN) is a group of computers and associated devices that share a common communications line and typically share the resources of a single processor or server within a small geographic area (for example, within an office building). Usually, the server has applications and data storage that are shared in common by multiple computer users. A local area network may serve as few as two or three users (for example, in a home network) or as many as thousands of users (for example, in an FDDI network).

L-BAND: A portion of the RF spectrum located between 500MHz and 1500MHz.

LEASED LINE: A dedicated circuit typically supplied by the telephone company.

LEO: Low earth orbit. An orbit 150 km to 300 km from the earth's surface.

LNB: Low noise blockdownconverter. An electronic part of a satellite earth station that is used to amplify the signal collected by the reflector and the feedhorn.

MCPC: Multi-channel per carrier. A signal comprised of multiple digital streams that are multiplexed into a single stream, which is then transmitted on a single carrier. This is typically used to combine multiple CDV signals into one.

MPEG: MPEG, the Moving Picture Experts Group, develops standards for digital video and digital audio compression. It operates under the auspices of the International Organization for Standardization. The MPEG standards are evolving, each designed for a different purpose.

MSO: Multiple system operator. A company that operates more than one cable TV system.

MULTI-CAST: The broadcast of messages to a selected group of workstations on a LAN, WAN or the Internet. Multicast is communication between a single device and multiple members of a device group.

MULTIPLEXING: A technique that combines multiple signals into one signal.

NAB: National Association of Broadcasters. A U.S.-based association that fosters and promotes radio and television broadcasting.

NASA: National Aeronautics and Space Administration.

NCTA: National Cable Television Association.

NETENG: Network Engineering.

NOISE: Energy always present on any signal.

ORBITAL SLOT: Specific location of a satellite in the geostationary arc, specified in degrees, east or west.

PAS: PanAmSat's international satellites. Also an abbreviation for PanAmSat.

PAYLOAD: Supports the primary mission of the satellite, the receipt and transmission of signals, and comprises systems that include receivers, multiplexers, high-powered amplifiers and signal processing.

PERIGEE: The lowest point in a satellite's orbit. The point in the orbit of a satellite when it is closest to the object around which it revolves.

PLATFORM: A structure in space containing multiple missions. A software operating system and/or open hardware, which an outsider could write software for.

POLARIZATION: The orientation of a transmitted/received signal. Signals can have circular or linear polarization.

POLAR ORBIT: A highly elliptical orbit that maximizes the satellite's exposure to the northern portion of the earth.

PSTN: Public switched telephony network. Refers to the world's collection of interconnected voice-oriented public telephone networks, both commercial and government-owned. It's also referred to as the plain old telephone service. It's the aggregation of circuit-switching telephone networks that has evolved from the days of Alexander Graham Bell. Today, it is almost entirely digital except for the final link from the central (local) telephone office to the user.

ROUTER: An intelligent device that supports connectivity by "routing" packets of information to their destination. Routers ensure that packets always arrive at their proper destination.

SBCA: Satellite Broadcasting and Communications Association. A not-for-profit national trade organization that aims to expand the use of satellite technology for the broadcast delivery of entertainment, news, information and educational programming.

SBS: Satellite Business Systems. A now-defunct business that aimed to deploy Ku-band satellites for enterprise and corporate use in the United States. The SBS fleet eventually came under PanAmSat's control. Only one SBS satellite remains in orbit, SBS-6.

SCPC: Single Channel Per Carrier. A scheme in which only one signal is loaded on a carrier. See MCPC.

SCRAMBLING: See encryption.

SHARED HUB: A satellite communications operations center that is shared among a number of separate network users, often used for VSAT operations.

SIA: Satellite Industry Association. An operating arm of the SBCA.

SIMPLEX OPERATION: Transmissions sent in only one direction of a telecommunications channel.

SNG: Satellite news gathering.

SNGV: Satellite news gathering vehicle. Mobile transmission facility used to uplink signals to a satellite from a remote location. Primarily used to cover special events and breaking news.

SOLAR ARRAY: A power generation method using solar cells.

SOLAR PANEL: A device on satellites that converts solar energy into electrical energy using solar cells.

SPACE SEGMENT: A term that describes the portion of the total communications satellite system that is physically located in orbit around the earth.

SPECTRUM: The range of electromagnetic radio frequencies used in transmission of voice, data and television.

SPOT BEAM: A satellite antenna designed to direct all of the satellite's power to a relatively compact area on earth.

SPOTbytes Internet connections: A bundled package, offering backbone network operators, international ISPs and corporate customers a one-stop shopping resource for satellite space segment, gateway transmission services and a dedicated Internet backbone connection.

STATIONKEEPING: The process of making in-orbit adjustments with small rocket thrusters attached to the satellite, keeping the satellite in its correct geosynchronous position.

STREAMING: Streaming video is a sequence of "moving images" that are sent in compressed form over the Internet and displayed by the viewer as they arrive. Streaming media is streaming video with sound. With streaming video or streaming media, a Web user does not have to wait to download a large file before seeing the video or hearing the sound. Instead, the media is sent in a continuous stream and is played as it arrives. The user needs a player, a special program that uncompresses and sends video data to the display and audio data to speakers. A player can be either an integral part of a browser or downloaded from the software maker's Web site.

SUN OUTAGE: When the sun passes behind a satellite in relation to the earth, and the sun's energy momentarily interferes with the satellite signals. Occurs two times each year during the spring and fall equinox.

SYMMETRIC CIRCUIT: A two-way satellite link with inbound and outbound paths set at the same rates.

TELEMETRY: The use of telecommunications for automatically indicating or recording measurements at a distance from the measuring instrument.

TCP: Transmission Control Protocol. TCP (Transmission Control Protocol) is a method used along with the Internet protocol to send data in the form of message units between computers over the Internet. While IP takes care of handling the actual delivery of the data, TCP takes care of keeping track of the individual units of data (called packets) that a message is divided into for efficient routing through the Internet.

T-1: Refers to bit rate of 1.544 million b/s for the United States. The European E-1 transmission bit rate is 2.048 Mb/s.

TDMA: Time Division Multiple Access. A form of multiple access where a single carrier is time-shared by many users. Signals from earth stations reaching the satellite consecutively are processed in time segments without overlapping.

TELEPHONY: The transmission of speech to distant places.

TELEPORT: Technical ground facility used for satellite communications. PanAmSat operates six domestic teleports: Atlanta, GA; Napa, CA; Fillmore, CA; Long Beach, CA; Castle Rock, CO. Homestead, FL; and Spring Creek, NY.

THRUSTER: A small rocket motor.

TI: Terrestrial interference. Interference to satellite signals caused by terrestrially generated signals, such as microwave towers, radar detectors and high-power electrical lines.

TRACKING: An earth station feature that allows for tracking inclined satellites.

TRANSFER ORBIT: An intermediate elliptical orbit used to reach geosynchronous orbit, where the apogee is the same altitude as the final operating orbit.

TRANSPONDER: A radio frequency path through a satellite with a specific bandwidth, uplink/downlink frequency and beam. Transponders can be sold in whole or can be segmented into smaller pieces of bandwidth.

TT&C: Tracking, telemetry and control. Refers to a satellite control station used to monitor onboard satellite operations and to direct satellite electronics and propulsion equipment.

TURNKEY: Refers to a system that is supplied, installed and sometimes managed by one vendor or manufacturer.

UHF: Ultra high frequency. The band in the 500 to 900 MHz range, including television channels 14 through 83.

UPLINK: The transmission of radio frequency signals to a satellite from an earth station.

VALUE-ADDED CARRIER: Carrier that orders services from common carriers that adds special features before retailing for use of circuits.

V-BAND: A higher frequency than Ka-band, operating from 40 to 50 GHz.

VHF: Very high frequency. The band in the 30 to 300 MHz range, including television channels 2 through 13.

VPN: A virtual private network is a private data network that makes use of the public telecommunication infrastructure, maintaining privacy by encrypting data before sending it through the public network and decrypting it at the receiving end. A virtual private network can be contrasted with a system of owned or leased lines that can only be used by one company. The idea of the VPN is to give the company the same capabilities at much lower cost by using the shared public infrastructure rather than a private one.

VSAT: Very small aperture terminal. Refers to small earth stations, usually 3 feet to 6 feet (0.9 meter to 1.8 meter) in diameter. A VSAT system is a satellite communications system that is typically used for corporations or rural telephony. A VSAT system consists of an antenna and the associated electronics. VSAT networks are widely used by department stores, gas stations and drug stores for verifying credit cards. VSAT systems can be used for voice, data and video.

WEBCAST SERVICES: High-speed, bandwidth-intensive IP broadcast network that will deliver streaming video, audio and data to edge-of-the-net servers around the globe. y

X-BAND: A portion of the RF spectrum located between 7 GHz and 8 GHz, which is dedicated to the U.S. military for satellite communications.

XIPS: Xenon Ion Propulsion System. A chemical propulsion system on satellites that uses charge particles and electromagnetism to generate thrust in order to move the satellite as well as maintain its position. XIPS is significantly more efficient than other propulsion systems and lessens the weight of the satellite, reducing launch costs.