⚠️ The 405 Express Lanes require a FasTrak® transponder. Existing transponders are accepted or purchase a new one here.. ⚠️ SMS texting scam regarding unpaid tolls for toll road users.You will need a FasTrak® Flex switchable transponder to travel on the 405 Express Lanes to receive a carpool discount. A FasTrak® Flex switchable transponder can be purchased through the 405 Express Lanes for $15. If you plan to travel on the Los Angeles Metro Express Lanes, Express Lanes in the Bay Area, 15 Express Lanes in Riverside County ...The TR2 Transponder is the world-leading standard in accuracy and built to last. Check your data online. Easy and Free online access to your practice and race results via the Speedhive platform. Everything a racer needs. Together with the TR2 Transponder comes the TR2 Cradle to charge your transponder in just 5 hours for 5 days of racing, and ...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, a flight transponder is an automated transceiver in an aircraft that emits a coded identifying … See more2020 MANDATE. An FAA mandate requires all aircraft flying in current Mode-C airspace to be equipped with ADS-B Out before 2020. Appareo has developed an ADS-B Out transponder that’s ideal for non-glass panel aircraft. Stratus ESG includes a 1090 ES transponder and certified WAAS GPS in the same box. It’s truly an “all-in-one box” …Learn what transponders are, what they’re used for, and the FAA regulations for different classes of airspace and equipment. Find out how to operate your aircraft’s …NXT-600™ for Business Jets. L3Harris’ NXT-600™ Mode S Transponder provides pilots with more efficient routing, while increasing airspace capacity, situational awareness and overall operational safety. The adaptor tray also enables quick and easily replacement of the Rockwell Collins TDR-94 and TDR-94D systems.NC Quick Pass is the N.C. Turnpike Authority’s all-electronic toll-collection program for the Triangle Expressway, Monroe Expressway and I-77 Express Lanes that offers drivers two ways to pay for tolls: a prepaid NC Quick Pass transponder account or the post-paid Bill by Mail program. A NC Quick Pass account is the e asiest and most cost-effective way to …Feb 27, 2024 · A Transponder we can say that it is a controller device that picks up and automatically responds to an incoming signal or whatever the input is coming in the machine, so this is a combination of transmitter and responder which is called a transponder. Also, a transponder is an electronic device that produces a response when it receives a radio ... TransPonder Happenings Mar 31 – Apr 6. March 31, 2024. Special Events. Financial Foundations Workshop on May 18, 2024 9:00 am Pride Night at PK Park on June 13, 2024 6:30 pm TransPonder's Recurring Events. TransPonder Book …Sticker Transponder Details. NC Quick Pass Sticker Transponder is designed for ease of use; you simply adhere it to your windshield. It offers the convenience of a smaller, more discreet profile at an affordable one-time cost. Installation: Sticks directly below the rearview mirror. Functionality: Operates on NC toll roads.Vantagens & Benefícios. Menor pressão durante a aplicação, agulha mais fina se comparada ao tamanho padrão (1.8 mm x 2.6 mm) Sem rejeições fisiológicas do produto no organismo do animal. Altamente bio compatível. Tamanho menor em relação ao tamanho padrão dos transponders de vidro (1.4 X 8 mm X 2 x 12 mm). Garantia de uma correta ...The airborne transponder receives interrogation codes on a 1030 MHz carrier wave from the ground station via one of two antennas located on the airframe. These signals are then amplified, demodulated and decoded in the transponder. The aircraft reply is coded, amplified and modulated as an RF transmission reply code on a 1090 MHz carrier wave.24/7 Residential, Commercial & Automotive Locksmith Services. (888) 947-5585. Transponder keys have become a standard in modern vehicles, offering enhanced security features. In this detailed guide, we'll delve into the understanding of transponder keys, explore the programming process, and discuss efficient methods for replacing or …Learn about the role, modes and functions of transponders in air traffic control and safety nets. Find out how transponder failures can affect operations and what actions and …Jul 23, 2021 · Optical transponder, also referred to as O-E-O (optical-electrical-optical) is an integrated part and is very crucial for the signal transmission in the whole WDM network system. An optical transponder works by converting the incoming signal from the end or client service to a WDM wavelength. This process is important in WDM systems and this ... transponder: [noun] a radio or radar set that upon receiving a designated signal emits a radio signal of its own and that is used especially for the detection, identification, and location of objects and in satellites for relaying communications signals.Transponder atau pemancar-penanggap (Inggris: transmitter-responder, transponder) yang artinya sebuah perangkat pemancar radio otomatis yang menerima, memperkuat, dan mengirimkan sinyal dalam frekuensi tertentu. Transponder pertama kali digunakan untuk identifikasi teman atau lawan yang memungkinkan otoritas militer mengidentifikasi …In addition to the airspace and altitude requirements, the FAA also has specific equipment requirements for transponders. The transponder must: Be an ‘operable coded radar beacon transponder’; and. Either have: Mode 3/A 4096 code capability, replying to Mode 3/A interrogations with the code specified by ATC; or.Transponder Types and Modes. The most basic type of transponder only transmits the programmed four-digit code. These Mode-A transponders are sometimes called 4096 transponders since they can send 4,096 different numerical codes. Note, the individual digits on the transponder are only programmable between zero and seven.A car transponder chip is a small electronic device fitted on the inside of a car key or fob. The chip is designed to communicate with the car’s immobiliser system, allowing the vehicle to be started only with the correct key. When the key is inserted into the ignition, the car’s immobiliser system sends a radio signal to the transponder ...How to apply. Online +. To open an E-ZPass MA account online you will need the following information: License plate number (s) - as listed on your vehicle registration. Vehicle (s) - make, model, and year. Payment information - credit card, debit card, or banking information. Your free transponder will be mailed to the address on your account.legacy transponder, the Lynx NGT-9000 is your ultimate panel mounted ADS-B solution. KEY FEATURES In addition to being a new-generation 1090ES transponder, the NGT-9000 brings a host of additional capabilities into your aircraft including: > 978 / 1090 MHz Dual-band receiver provides traffic and weather > Patented L3Harris Lynx TailYour interior transponder must be mounted to your windshield, just to the right of the arm holding your rear view mirror and below any tinting. Make sure the arrows on the transponder are pointing upward. Peel back the plastic film on the fastener strips and attach the transponder to your clean, dry windshield.Below is an overview of toll costs: If you are a current E-ZPass customer, your costs have not increased. If you are not currently a New Hampshire E-ZPass customer, you can purchase a New Hampshire E-ZPass transponder on the NH EZ-Pass website for $6.69. New Hampshire customers (with class 1-4 vehicles) receive a 30% discount on New …Transponder pricing varies by toll agency. Indiana E-ZPass 2-axle transponders are $25.00. Your opening balance is $10.00 ($8.00 for retail transponders) and a one-time $15.00 transponder issuance fee. Shipping and handling is $7.00 per order when ordered online or from the Customer Care Center. The transponder has a switch so that you can identify whether you meet the vehicle occupancy criteria. The transponder works the same as a standard E-ZPass on all other roads. If you want to use Express Lanes and don’t plan on having enough people to qualify to drive toll-free, you may use a standard E-ZPass transponder for travel. E-ZPass ... Define transponder. transponder synonyms, transponder pronunciation, transponder translation, English dictionary definition of transponder. n. A radio or radar transmitter-receiver activated for transmission by reception of a predetermined signal.The transponder was introduced in WWII by the British, to be able to identify friendly aircraft in the sky. The system was called a "parrot", which lead to terms like "squawk your parrot" and "strangle your parrot". The system was later adopted by the US under the name "identification of friend or foe", which is still used in the US military today. A transponder (XPDR) is a receiver/transmitter which will generate a reply signal upon proper interrogation; the interrogation and reply being on different frequencies. (ICAO) Transponders first came into use to enable military authorities to identify friendly aircraft, which transmitted a coded signal when interrogated by military radar. ping200X TSO Certified Mode S ADS-B Transponder for UAS ping200X is the premier FAA TSO Certified Mode S ADS-B OUT transponder for UAS. Enabling airspace access, regulator and Air Navigation Service …2020 MANDATE. An FAA mandate requires all aircraft flying in current Mode-C airspace to be equipped with ADS-B Out before 2020. Appareo has developed an ADS-B Out transponder that’s ideal for non-glass panel aircraft. Stratus ESG includes a 1090 ES transponder and certified WAAS GPS in the same box. It’s truly an “all-in-one box” …A satellite transponder is a vital element of communication satellites that has garnered considerable attention in the field of telecommunications. It’s responsible for receiving, amplifying, and …It is a Search and Rescue Transponder (SART) that uses Automatic Identification System (AIS) technology to provide location information to search and rescue units in the event of an emergency. It works by transmitting a distress signal on the AIS frequency, which can be picked up by other AIS-enabled vessels or shore-based …Oct 31, 2022 · Hi. In this video we look at what is a transponder on an aircraft and the different modes or types of transponders available. We see what information these t... Finisar SFP+ Active Optical Cable for 10G and 25G Ethernet. Also available with Connectivity Diagnostics® visual fault alert. Finisar 40 Gb/s to 400 Gb/s Parallel Active Optical Cable for 40, 100 and 400 Gigabit Ethernet; InfiniBandTM QDR, FDR, EDR, HDR and NDR; and Intel® Omni-Path Architecture. 40G also available with Connectivity ... ping200XR It’s in There – Mode S ADS-B Transponder with Integrated Aviation GPS ping200XR combines the same technology used in the TSO certified ping200X transponder with an internal aviation GPS. Enabling airspace access, regulator, and Air Navigation Service Provider (ANSP) acceptance worldwide, ping200XR enables your …Collins Aerospace’s TDR-94D Transponder is an all solid-state, crystal-controlled receiver/transmitter specifically designed for TCAS-II-equipped business aircraft and regional airliners with 28 V DC electrical systems and limited space. It is the airborne portion of the Air Traffic Control Radar Beacon System.Transponder key means “transmitter and responder,” and it refers to an electronic chip embedded in the head of the key that transmits a signal to the car’s engine computer. A transponder key is a type of key that has an embedded chip, also known as a transponder chip. The chip is a small, radio-frequency identification (RFID) tag that ...Transponder definition: a radio, radar, or sonar transceiver that automatically transmits a signal upon reception of a designated incoming signal. See examples of TRANSPONDER used in a sentence.MYLAPS offers specialized transponders and chips for different sports, such as car, bike, MX, kart, RC, drone and more. You can get your own personal transponder, renew your …Welcome to the official MYLAPS Transponder Shop. This is your place to buy MYLAPS transponders, chips, accessories and more, as well as find additional information about our products. MYLAPS offers timing devices for all types of sports. Our products include transponders and chips for car and bike racing, MX, RC racing, karting, cycling, ...Nomad is a new, portable AIS transponder with built-in GPS from Digital Yacht. Designed for recreational boaters and professional mariners, it offers a full function, Class B AIS transponder with a wireless and USB interface built in for tablets and PCs – all in a portable, compact package. It addresses the needs of so many boaters who want a ...The transponder communicates with toll readers using radio frequency identification (RFID) technology. To block this signal, you’ll need to use materials or techniques that interrupt RFID communication effectively, thereby preventing your transponder from being read as you pass through a toll.Conclusion. In this guide, we discovered that a transponder key is a key that relays a radio frequency signal to the immobilizer in your car when you go through the ignition startup process. It adds an extra layer of security due to the RFID chip that is installed in it and has a couple of other additional benefits.Please login to access your E-ZPass MA account. Select the Type of Login below and then enter the required information. Type of Login. User Login.A transponder is a radio or radar set that emits a signal of its own when receiving a signal from another device. It is used for detection, identification, and location of objects and in …Learn the difference between transponder modes (A, C, S) and codes (squawk codes) and how they help ATC and other aircraft track and identify your aircraft. …The aircraft has two ATC transponders (XPDR) which are controlled by a control panel (ATC/TCAS) on the center pedestal. Only the selected XPDR operates. The XPDR automatically responds to requests: From the ATC, to ensure effective air traffic surveillance. From other aircraft that have a TCAS, to ensure that traffic alerts are … A transmitter is a separate electronic component that generates a radio frequency ( RF) current or radio waves. These waves are used in communication systems to transfer data like audio, video, etc. A transceiver, on the other hand, can both send and receive digital signals. Macrocell, small cell and femtocell cellular base stations are fixed ... PRODUCT DESCRIPTION. The AISLink CB2 AIS Transponder is a fully compliant, waterproof Class B+ transceiver designed to help avoid collisions. Using advanced SOTDMA (Self Organized Time Division Multiple Access) technologies from Class A transponders, the AISLink CB2 marine AIS system features inherent advantages, …Immobiliser sign. An immobiliser or immobilizer is an electronic security device fitted to a motor vehicle that prevents the engine from being started unless the correct key ( transponder or smart key) is present. This prevents the vehicle from being "hot wired" after entry has been achieved and thus reduces motor vehicle theft.Apr 24, 2023 · While transceivers and transponders are commonly used in RF applications, muxponders are added to the mix in the optical communications domain. Optical transceivers are used in fiber optic networks to receive and transmit optical signals in a single module. Optical transceivers use a range of optical wavelengths, typically from 850 to 1,550 ... A transponder is a device that receives and retransmits signals based on a fixed frequency. It can be used in satellite communication, aviation, radar systems, and …Transponder. Secondary radar depends on a transponder (short-for Transmitter-responder) in the airplane to respond to interrogations from the ground station to make the aircraft visible and to report additional information like the aircraft’s altitude.. Figure 1 shows an older one transponder. The replays code for Mode 1 and 3/A can be choosen with …It also complies with IEC 60945 (EMC and environmental conditions). The FA50 consists of a transponder unit with GPS antenna. A VHF antenna is required and should be supplied separately. The transponder contains a VHF transmitter, two TDMA receivers on two parallel VHF channels, interface, communication processor, and internal GPS receiver. Headlamp Sticker Transponder Installation Instructions. Motorcycle transponders are sticker transponders made specifically for motorcycles. They can be mounted to the headlamp lens or cover. If you have a motorcycle listed on your account, you can request a motorcycle sticker transponder by calling our Customer Service Call Center at 949-727-4800. The GTX 328 transponder is powered on by pressing the STBY, ALT or ON keys, or by a remote avionics master switch (if applicable). After power on, a start-up page is displayed while the unit performs a self test. Mode Selection Keys OFF Powers off the GTX 328. Pressing STBY, ON or ALT Key powers on the transponder displaying the last activeTransPonder, Eugene, Oregon. 3,226 likes · 96 talking about this · 2 were here. This page is a public page to share information about the TransPonder non-profit organization.Timekeeping in car racing is a tough challenge. That's why timekeepers, event organizers, and tracks from all over the world rely on MYLAPS technology. In this shop you can buy MYLAPS transponders and accessories for car racing. With a MYLAPS transponder you can use the free MYLAPS Speedhive app to check your personal results, follow races, …Calculate tolls and fuel cost to travel across US. Calculate routes, tolls and fuel costs for your travel by car, truck, taxi, bus, caravans (with or without a trailer) and EV in the US and other North American countries using TollGuru Trip Calculator.It also shows the cheapest, fastest and other optimal routes to your destination along with toll plaza(s) location en …⚠️ The 405 Express Lanes require a FasTrak® transponder. Existing transponders are accepted or purchase a new one here.. ⚠️ SMS texting scam regarding unpaid tolls for toll road users.NC Quick Pass is the N.C. Turnpike Authority’s all-electronic toll-collection program for the Triangle Expressway, Monroe Expressway and I-77 Express Lanes that offers drivers two ways to pay for tolls: a prepaid NC Quick Pass transponder account or the post-paid Bill by Mail program. A NC Quick Pass account is the e asiest and most cost-effective way to … With the MYLAPS personal transponder hundreds of thousands of sportspeople have full access to their results to view, analyze and share them. And they do not need to collect a rental transponder at each event. We provide timing systems at many sports locations and racetracks. To get your own personal transponder choose your sport and ... To find the transponder number on your SunPass PRO, look for a set of numbers printed directly on the device. Usually, this is on the front of the transponder near the barcode. The number is often beneath the barcode, labeled specifically as “Transponder Number” and can be up to 12 digits long. Ensure you do not confuse this …giving your transponder about 45-50 seconds to become operational. As soon as you are airborne, turn the Function Selector to ON, which places the K T 76A in normal Mode A operation. If your aircraft is equipped with an encoding altimeter, turn the Function Selector to the ALT (Altitude) position, for altitude reporting (Mode C) to ATC.Satellite Communication - Transponders. The subsystem, which provides the connecting link between transmitting and receiving antennas of a satellite is known as Transponder. It is one of the most important subsystem of space segment subsystems. Transponder performs the functions of both transmitter and receiver (Responder) in a satellite.Transponder slots fit a standards-based SFP, SFP+, XFP and/or CFP, providing the user with a modular, pluggable solution for both service and line sides. This architecture enables easy growth by simply adding optics to add services. PacketLight’s transponder devices provide 1+1 protection, remote management, and embedded OSC channel.2020 MANDATE. An FAA mandate requires all aircraft flying in current Mode-C airspace to be equipped with ADS-B Out before 2020. Appareo has developed an ADS-B Out transponder that’s ideal for non-glass panel aircraft. Stratus ESG includes a 1090 ES transponder and certified WAAS GPS in the same box. It’s truly an “all-in-one box” …⚠️ The 405 Express Lanes require a FasTrak® transponder. Existing transponders are accepted or purchase a new one here.. ⚠️ SMS texting scam regarding unpaid tolls for toll road users.Oct 31, 2022. Satellite transponder provides a communication channel between the transmitting & the receiving antenna on the satellite with the base station on the ground. A transponder performs the function of both the transmitter and the receiver in a satellite. Transponders mainly perform the function of receiving a given signal and then ... em-trak B923 Class B CSTDMA AIS Transponder with Integrated Splitter. $746.00. Buy. SI-TEX MDA-1 Metadata Class B AIS Transceiver w/Internal GPS. $799.00. Buy. AMEC CAMINO-108S Class B AIS Transponder with integrated splitter. $799.99 $779.99. Select Options. NMEA 2000™, NMEA 0183/-HS Connectivity. With the plug-and-play functionality of NMEA 2000™, the MA-510TR can connect to a NMEA 2000™ network (an external plotter, marine radar and VHF radio). Using NMEA 0183/-HS connectivity, the transponder can connect to a transceiver, plotter device, marine radar, external GPS receiver, or switch button.Calculate tolls and fuel cost to travel across US. Calculate routes, tolls and fuel costs for your travel by car, truck, taxi, bus, caravans (with or without a trailer) and EV in the US and other North American countries using TollGuru Trip Calculator.It also shows the cheapest, fastest and other optimal routes to your destination along with toll plaza(s) location en …Memory Spot is a passive transponder that contains a chip capable of storing large data files such as digital photographs, databases or musical selections. The transponder, which is a sophisticated, short-range RFID (radio frequency identification) tag, can be incorporated into any object and can be worn by a person or animal. Memory Spot is ...legacy transponder, the Lynx NGT-9000 is your ultimate panel mounted ADS-B solution. KEY FEATURES In addition to being a new-generation 1090ES transponder, the NGT-9000 brings a host of additional capabilities into your aircraft including: > 978 / 1090 MHz Dual-band receiver provides traffic and weather > Patented L3Harris Lynx TailWhat to expect from Beyond Light's new Exotics and gear.Watch on YouTube How to complete Destiny 2 Augment Triumphs step-by-step, from sourcing a Braytech Transponder to finding a Techno Squad Leader Satellite Communication - Transponders. The subsystem, which provides the connecting link between transmitting and receiving antennas of a satellite is known as Transponder. It is one of the most important subsystem of space segment subsystems. Transponder performs the functions of both transmitter and receiver (Responder) in a satellite. The Transponder Node can be attached to both Players and Dinosaurs (tamed and untamed). You can then track all Nodes with the Transponder Tracker. To place on a creature, you need to equip a Transponder Tracker with one or more Nodes in your inventory, then use your Fire key (defaults to Mouse1) on the Dinosaur. May disappear …The RC4 Decoder determines the exact time at which each transponder passes the detection loops. The decoder sends this data the timekeeper’s computer. The decoder has a built-in practice mode that allows automated uploads of practice results to mylaps.com, without the need of a timekeeper. Please note all new RC4 Decoders come with …Aug 28, 2023 · Optical Muxponders: An optical muxponder is an integral aspect of network enhancement, which is often used in fiber optic or blended networks. It helps increase the fiber capacity in terms of data transmission by reducing wavelengths. The muxponder combines multiple wavelengths into a single unit with the help of optical transport network (OTN ... TransPonder is a nonprofit that supports and educates trans/gender-diverse people and their allies in Eugene, Oregon. It offers various events, workshops, and …A satellite transponder is a vital element of communication satellites that has garnered considerable attention in the field of telecommunications. It’s responsible for receiving, amplifying, and … Satellite Transponder. Following are the basic functions of a transponder. • It does frequency translation i.e. converts frequency from one band to the other band. As shown in the figure-1 C-band transponder converts frequency in 6 GHz band to frequency in 4 GHz band range. A transponder (short for transmitter-responder and sometimes abbreviated to XPDR, XPNDR, TPDR or TP) is an electronic device that produces a response when it receives a radio-frequency …Steps to Return Your Transponder. Locate a Return Address: You’ll find the necessary address to which you can return your transponder on the respective E-ZPass New York Customer Service Center or through your state’s specific E-ZPass service center’s website. Prepare Your Transponder for Mail: Wrap your transponder in …A transponder (short for transmitter-responder and sometimes abbreviated to XPDR, XPNDR, TPDR or TP) is an electronic device that produces a response when it receives a radio-frequency …
mPTX Direct Powered Transponder.ID Numbers: Main 7 Digit ID/ALT 7 Digit IDSystem Compatibility: Compatible with AMBrc2, AMBrc3, Mylaps RC3 and Mylaps ... view details. £53.40 View details Add to wishlist ADD TO YOUR BASKET. MRT mPTX Transponder - Heatshrink Kit. £42.60 .... Grand wailea maui location
legacy transponder, the Lynx NGT-9000 is your ultimate panel mounted ADS-B solution. KEY FEATURES In addition to being a new-generation 1090ES transponder, the NGT-9000 brings a host of additional capabilities into your aircraft including: > 978 / 1090 MHz Dual-band receiver provides traffic and weather > Patented L3Harris Lynx Tail A transmitter is a separate electronic component that generates a radio frequency ( RF) current or radio waves. These waves are used in communication systems to transfer data like audio, video, etc. A transceiver, on the other hand, can both send and receive digital signals. Macrocell, small cell and femtocell cellular base stations are fixed ... Squawk codes are what air traffic control (ATC) use to identify aircraft when they are flying. They are unique four-digit numbers and range from 0000 to 7777; some of which are fixed values signifying specific scenarios (see below), others being randomly generated by ATC. At the dawn of commercial aviation, the position of an aircraft was ...Below is an overview of toll costs: If you are a current E-ZPass customer, your costs have not increased. If you are not currently a New Hampshire E-ZPass customer, you can purchase a New Hampshire E-ZPass transponder on the NH EZ-Pass website for $6.69. New Hampshire customers (with class 1-4 vehicles) receive a 30% discount on New …Transponder: When you mount the transponder inside your model you have to search for a position where the transponder has direct visibility with the bridge. Otherwise the infrared signal is not delivered to the receiver modules. The transponder can be connected directly to the radio receiver in the model.24/7 Residential, Commercial & Automotive Locksmith Services. (888) 947-5585. Transponder keys have become a standard in modern vehicles, offering enhanced security features. In this detailed guide, we'll delve into the understanding of transponder keys, explore the programming process, and discuss efficient methods for replacing or …November 27, 2023. If your E-ZPass starts beeping continuously, it’s trying to signal something important. Usually, this beeping can occur if it detects a low battery or if there’s an issue with your account. It’s your cue to pay attention to the device to avoid any toll-related surprises on your next trip. Contents show. Satellite Communication - Transponders. The subsystem, which provides the connecting link between transmitting and receiving antennas of a satellite is known as Transponder. It is one of the most important subsystem of space segment subsystems. Transponder performs the functions of both transmitter and receiver (Responder) in a satellite. The transponder has a switch so that you can identify whether you meet the vehicle occupancy criteria. The transponder works the same as a standard E-ZPass on all other roads. If you want to use Express Lanes and don’t plan on having enough people to qualify to drive toll-free, you may use a standard E-ZPass transponder for travel. E-ZPass ... Other articles where transponder is discussed: satellite communication: How satellites work: …with the use of a transponder—an integrated receiver and transmitter of radio signals. A satellite has to withstand the shock of being accelerated during launch up to the orbital velocity of 28,100 km (17,500 miles) an hour and a hostile space environment … A transponder (XPDR) is a receiver/transmitter which will generate a reply signal upon proper interrogation; the interrogation and reply being on different frequencies. (ICAO) Transponders first came into use to enable military authorities to identify friendly aircraft, which transmitted a coded signal when interrogated by military radar. .