The Automatic Transmitter Identification System (ATIS) is a

communications protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any variation of a physical quantity. The protocol defines the rules, syntax, semantics (computer science), sem ...

used for the

station identification Station identification (ident, network ID, channel ID or bumper (broadcasting), bumper) is the practice of radio and television stations and broadcast network, networks identifying themselves on-air, typically by means of a call sign or brand na ...

of television channels carried on

satellite television Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location.ITU Radio Regulations, Section IV. Radio Stations and Systems ...

. ATIS is only required for

analog television Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, instantaneous phase and frequency, ...

transmission and only via satellites or earth stations under

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

jurisdiction. It is continuously repeated whilst an earth station is using a transponder on a satellite. The

Federal Communications Commission The Federal Communications Commission (FCC) is an independent agency of the United States government that regulates communications by radio, television, wire, internet, wi-fi, satellite, and cable across the United States. The FCC maintains j ...

(FCC) rules for ATIS are set forth in 47 CFR §25.281. The system was developed in response to the " Captain Midnight" satellite jamming incident. In 2009, HBO and Elmer Musser were awarded a

Technology & Engineering Emmy Award The Technology and Engineering Emmy Awards, or Technology and Engineering Emmys, are one of two sets of Emmy Awards that are presented for outstanding achievement in engineering development in the television industry. The Technology and Engineer ...

for ATIS. ATIS is a

Morse code Morse code is a telecommunications method which Character encoding, encodes Written language, text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code i ...

transmission sent on a subcarrier of 7.1 MHz and must activate automatically any time the station is transmitting. The center frequency must be no more than 25 kHz from this nominal value and the

frequency deviation Frequency deviation (f_) is used in FM radio to describe the difference between the minimum or maximum extent of a frequency modulated signal, and the nominal center or carrier frequency. The term is sometimes mistakenly used as synonymous with fre ...

must be no more than 25 kHz peak when being modulated. Injection must be at a minimum of −26 dB referenced to the unmodulated carrier. The tone used to modulate the subcarrier is nominally 1,200 Hz, but may vary by as much as 800 Hz (400 to 2,000 Hz). The ATIS message is sent at a transmission rate of 15 to 25 words per minute and must not exceed 30 seconds in its entire length. The message includes the FCC-assigned callsign of the earth station, its

telephone number A telephone number is the address of a Telecommunications, telecommunication endpoint, such as a telephone, in a telephone network, such as the public switched telephone network (PSTN). A telephone number typically consists of a Number, sequ ...

, a ten-digit

serial number A serial number (SN) is a unique identifier used to ''uniquely'' identify an item, and is usually assigned incrementally or sequentially. Despite being called serial "numbers", they do not need to be strictly numerical and may contain letters ...

, and sometimes other information which is voluntary. The telephone number must immediately connect to personnel who can resolve radio interference and other frequency coordination issues. The serial number cannot be easily changed. ATIS encoders must be included in the uplink airchain of all transmitters as of March 1, 1991 "in a method that cannot easily be defeated". Other subcarriers piggybacked on the

video Video is an Electronics, electronic medium for the recording, copying, playback, broadcasting, and display of moving picture, moving image, visual Media (communication), media. Video was first developed for mechanical television systems, whi ...

carrier are also included in transmissions, often at 6.2 MHz and 6.8 MHz, just above the bandpass of the video signal (even if scrambled). These carry left and right

stereo Stereophonic sound, commonly shortened to stereo, is a method of sound reproduction that recreates a multi-directional, 3-dimensional audible perspective. This is usually achieved by using two independent audio channels through a configurat ...

audio and second audio program, and sometimes

radio station Radio broadcasting is the broadcasting of audio (sound), sometimes with related metadata, by radio waves to radio receivers belonging to a public audience. In terrestrial radio broadcasting the radio waves are broadcast by a land-based rad ...

s or

radio network There are two types of radio network currently in use around the world: the one-to-many (simplex communication) broadcast network commonly used for public information and mass media, mass-media entertainment, and the two-way radio (Duplex (teleco ...

s which may be unrelated to the

television network A television broadcaster or television network is a telecommunications network for the distribution of television show, television content, where a central operation provides programming to many television stations, pay television providers or ...

. Backhauls are too intermittent for such uses but may carry in-house private audio channels instead. Because all of these, including ATIS, are all audio, they can all be tuned by an analog TVRO receiver. However,

digital television Digital television (DTV) is the transmission of television signals using Digital signal, digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an ...

has overtaken analog because multiple channels can be transmitted on one transponder. These signals carry their station ID as

data Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted for ...

instead.

References

{{reflist Satellite television Broadcast engineering