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Radio-frequency identification ( RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder called a tag, a radio receiver, and a transmitter. When triggered by an electromagnetic interrogation pulse from a nearby RFID reader device, the tag transmits ...
Radar beacon. Racon signal as seen on a radar screen. This beacon receives using sidelobe suppression and transmits the letter "Q" in Morse code near Boston Harbor (Nahant) 17 January 1985. Radar beacon (short: racon) is – according to article 1.103 of the International Telecommunication Union's (ITU) ITU Radio Regulations (RR) [1 ...
Yellow dots on white paper, produced by color laser printer (enlarged, dot diameter about 0.1 mm) A Machine Identification Code (MIC), also known as printer steganography, yellow dots, tracking dots or secret dots, is a digital watermark which certain color laser printers and copiers leave on every printed page, allowing identification of the device which was used to print a document and ...
A UPC barcode. The Universal Product Code (UPC or UPC code) is a barcode symbology that is used worldwide for tracking trade items in stores.. The chosen symbology has bars (or spaces) of exactly 1, 2, 3, or 4 units wide each; each decimal digit to be encoded consists of two bars and two spaces chosen to have a total width of 7 units, in both an "even" and an "odd" parity form, which enables ...
A heliograph (from Ancient Greek ἥλιος (hḗlios) 'sun', and γράφειν (gráphein) 'to write') is a solar telegraph [1] system that signals by flashes of sunlight (generally using Morse code) reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter. [2]
Duff's device. In the C programming language, Duff's device is a way of manually implementing loop unrolling by interleaving two syntactic constructs of C: the do - while loop and a switch statement. Its discovery is credited to Tom Duff in November 1983, when Duff was working for Lucasfilm and used it to speed up a real-time animation program.
The Type Allocation Code (TAC) is the initial eight- digit portion of the 15-digit IMEI and 16-digit IMEISV codes used to uniquely identify wireless devices. The Type Allocation Code identifies a particular model (and often revision) of wireless telephone for use on a GSM, UMTS, LTE, 5G NR, iDEN, Iridium or other IMEI-employing wireless network ...
The use of stingrays by United States law enforcement is an investigative technique used by both federal and local law enforcement in the United States to obtain information from cell phones by mimicking a cell phone tower. The devices which accomplish this are generically known as IMSI-catchers, but are commonly called stingrays, a brand sold ...