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28-469: To participate, a driver signs up through the EZ TAG website, via telephone, or at one of the store locations. Next, the customer receives a small, white radio frequency transponder which must be affixed to the inside of their windshield behind their rear view mirror. Finally, when passing through a toll plaza, the driver chooses lanes specially equipped with sensors that can read EZ TAG transmitters and deduct

56-421: A bent pipe (i.e., u-bend ) principle, sending back to Earth what goes into the conduit with only amplification and a shift from uplink to downlink frequency. However, some modern satellites use on-board processing, where the signal is demodulated, decoded, re-encoded and modulated aboard the satellite. This type, called a "regenerative" transponder, is more complex, but has many advantages, such as improving

84-455: A flight transponder is an automated transceiver in an aircraft that emits a coded identifying signal in response to an interrogating received signal. In a communications satellite , a satellite transponder receives signals over a range of uplink frequencies, usually from a satellite ground station ; the transponder amplifies them, and re-transmits them on a different set of downlink frequencies to receivers on Earth, often without changing

112-526: A 915 MHz EZ TAG, a copy of the ROM 2048-bit chip must be dumped and loaded into another ROM chip and a matched inductance of the RFID EZ TAG surface needs to be constructed. Blank 915 MHz RFID pads can be bought online. As of January 2008, three different sets of EZ Tags have been released. The differences are purely cosmetic. Despite the similarity in the names, EZ Tags are not compatible with

140-414: A lap they swipe or touch the receiver which is connected to a computer and log their lap time. NASCAR uses transponders and cable loops placed at numerous points around the track to determine the lineup during a caution period. This system replaced a dangerous race back to the start-finish line . Many modern automobiles have keys with transponders hidden inside the plastic head of the key. The user of

168-473: A resident's car with simple transponder is parked in the vicinity, any vehicle can come up to the automated gate, triggering the gate interrogation signal , which may get an acceptable response from the resident's car. Such units properly installed might involve beamforming , unique transponders for each vehicle, or simply obliging vehicles to be stored away from the gate. Transponder (satellite communications) A communications satellite 's transponder

196-520: A result, differences in transponder functionality also might influence the functional description of related optical modules like transceivers and muxponders . Another type of transponder occurs in identification friend or foe (IFF) systems in military aviation and in air traffic control secondary surveillance radar (beacon radar) systems for general aviation and commercial aviation . Primary radar works best with large all-metal aircraft, but not so well on small, composite aircraft. Its range

224-418: A ship's radar screen. Sonar transponders operate under water and are used to measure distance and form the basis of underwater location marking, position tracking and navigation . Electronic toll collection systems such as E-ZPass in the eastern United States use RFID transponders to identify vehicles. Transponders are used in races for lap timing. A cable loop is dug into the race circuit near to

252-405: Is also limited by terrain and rain or snow and also detects unwanted objects such as automobiles, hills and trees. Furthermore, it cannot always estimate the altitude of an aircraft. Secondary radar overcomes these limitations but it depends on a transponder in the aircraft to respond to interrogations from the ground station to make the plane more visible. Depending on the type of interrogation,

280-555: Is greatly reduced if it is not mounted on a glass substrate. This range reduction is so much that not having a tag properly mounted will result in it not reading at all in toll lanes. These characteristics are much different compared to the old battery tags, which would read fine if not mounted properly. As such, some toll patrons attempt to hold up their sticker tags when driving through the toll lanes, and appear mystified when they do not work as their old tags did. The new tag uses three different protocols, or communications methods, with

308-412: Is mandatory in controlled airspace in many countries. Some countries have also required, or are moving toward requiring, that all aircraft be equipped with Mode S, even in uncontrolled airspace . However, in the field of general aviation there have been objections to these moves, because of the cost, size, limited benefit to the users in uncontrolled airspace, and, in the case of balloons and gliders ,

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336-428: Is the series of interconnected units that form a communications channel between the receiving and the transmitting antennas. It is mainly used in satellite communication to transfer the received signals. A transponder is typically composed of: Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz. Most transponders operate on

364-492: The E-ZPass system in the northeast U.S. In November 2015, HCTRA announced a new Cash Reloadable EZ Tag. The EZ Tag by BancPass can be reloaded with cash at major retailers, or the user can reload online using a debit or credit card. The EZ Tag by BancPass also differs from the standard EZ Tag by not reloading automatically. The user is notified when the account balance gets low, and the user can choose when and how much to put on

392-532: The Doppler shift and thus infer range and speed from a communication signal without allocating power to a separate ranging signal. A transponder equivalent ( TPE ) is a normalized way to refer to transponder bandwidth. It simply means how many transponders would be used if the same total bandwidths used only 36 MHz transponders. So, for example, the ARSAT-1 has 24 IEEE K u band transponders: 12 with

420-500: The EZ TAG customer is not compromised in this process because the EZ TAG database and the AVI system are not interconnected. In May 2006, HCTRA introduced a new version of the transponder tag. Instead of battery-powered radio transmitters, the new tags are adhesive stickers with a button-sized microchip in the middle of, and a reflective antenna system throughout the tag. These new tags are sold, rather than rented, so they help save money over

448-429: The appropriate amount from their accounts. Houston Transtar uses EZ TAG sensors, which are placed at numerous points across Greater Houston, for their Automatic Vehicle Identification (AVI) traffic monitoring system. By tracking the movement of individual transponder tags (EZ TAG user vehicles) over the city, the system can generate real time traffic information for use by the general public. The personal information about

476-546: The car may not even be aware that the transponder is there, because there are no buttons to press. When a key is inserted into the ignition lock cylinder and turned, the car's computer sends a signal to the transponder. Unless the transponder replies with a valid code, the computer will not allow the engine to be started. Transponder keys have no battery; they are energized by the signal itself. Transponders may also be used by residents to enter their gated communities . However, having more than one transponder causes problems. If

504-695: The content of the received signal or signals. A communications satellite ’s channels are called transponders because each is a separate transceiver or repeater . With digital video data compression and multiplexing , several video and audio channels may travel through a single transponder on a single wideband carrier . Original analog video only has one channel per transponder, with subcarriers for audio and automatic transmission identification service ( ATIS ). Non-multiplexed radio stations can also travel in single channel per carrier (SCPC) mode, with multiple carriers (analog or digital) per transponder. This allows each station to transmit directly to

532-461: The life of the tag by eliminating the monthly $ 1 rental fee. The battery tag's $ 15 security deposit can be applied to the purchase of the sticker tag. Removing the sticker after placement has a high probability of either separating the chip from the antenna, de-tuning the antenna from its designated frequency, or both, therefore invalidating the tag for future use. The tag also relies on the windshield for an amplification effect, and its effective range

560-466: The power requirements during long flights. Transponders are used on some military aircraft to ensure ground personnel can verify the functionality of a missile’s flight termination system prior to launch. Such radar-enhancing transponders are needed as the enclosed weapon bays on modern aircraft interfere with prelaunch, flight termination system verification performed by range safety personnel during training test launches. The transponders re-radiate

588-463: The satellite, rather than paying for a whole transponder or using landlines to send it to an Earth station for multiplexing with other stations. NASA distinguishes between a " transceiver " and "transponder". A transceiver has an independent transmitter and receiver packaged in the same unit. In a transponder the transmit carrier frequency is derived from the received signal. The frequency linkage allows an interrogating ground station to recover

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616-530: The satellite, rather than paying for a whole transponder, or using landlines to send it to an earth station for multiplexing with other stations. In fiber-optic communications , a transponder is the element that sends and receives the optical signal from a fiber . A transponder is typically characterized by its data rate and the maximum distance the signal can travel. The term "transponder" can apply to different items with important functional differences, mentioned across academic and commercial literature: As

644-692: The signal to noise ratio as the signal is regenerated from the digital domain, and also permits selective processing of the data in the digital domain. With data compression and multiplexing , several video (including digital video ) and audio channels may travel through a single transponder on a single wideband carrier . Original analog video only had one channel per transponder, with subcarriers for audio and automatic transmission-identification service ATIS . Non-multiplexed radio stations can also travel in single channel per carrier (SCPC) mode, with multiple carriers (analog or digital) per transponder. This allows each station to transmit directly to

672-850: The signals allowing for much longer communication distances. The International Maritime Organization 's International Convention for the Safety of Life at Sea (SOLAS) requires the Automatic Identification System (AIS) to be fitted aboard international voyaging ships with 300 or more  gross tonnage  (GT), and all passenger ships regardless of size. AIS transmitters/receivers are generally called transponders , but they generally transmit autonomously, although coast stations can interrogate class B transponders on smaller vessels for additional information. In addition, navigational aids often have transponders called RACON (radar beacons) designed to make them stand out on

700-436: The start/finish line. Each individual runner or car has an active transponder with a unique ID code. When the individual passes the start/finish line, the lap time and the racing position is shown on the score board. Passive and active RFID systems are used in motor sports , and off-road events such as Enduro and Hare and Hounds racing, the riders have a transponder on their person, normally on their arm. When they complete

728-501: The tag readers—ATA, eGo and SeGo. The protocol used in Houston is ATA for automatic equipment identification; however, a driver in Houston can conceivably use the tag in another state where the other protocols are used. In addition, the tags support ANSI INCITS 256-2001 and ISO 10374. The tag is read by scanners as far as 31.5 feet (9.6 m) at 915 MHz, and the tag features a 2048-bit read/write passive memory. To duplicate

756-467: The transponder sends back a transponder code (or "squawk code", Mode A) or altitude information (Mode C) to help air traffic controllers to identify the aircraft and to maintain separation between planes. Another mode called Mode S (Mode Select) is designed to help avoiding over-interrogation of the transponder (having many radars in busy areas) and to allow automatic collision avoidance. Mode S transponders are backward compatible with Modes A and C. Mode S

784-464: The user's account. The EZ Tag by BancPass is available online, at H-E-B grocery stores and at Corner Store by Valero. Accounts can be reloaded online or at any H-E-B, CVS or Corner Store by Valero. Transponder In telecommunications , a transponder is a device that, upon receiving a signal, emits a different signal in response. The term is a blend of transmitter and responder . In air navigation or radio frequency identification ,

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