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Shop Bundle & Save41 terms every locksmith supplier should define properly — transponder chip families, remote architectures, programming jobs and the identifiers that match a part to a vehicle. Written by the trade, for the trade.
Every definition below is written to be technically precise and short enough to use mid-job. When you already have the code off the customer's fob, skip straight to the FCC ID directory to cross-reference it against stock, or use Find My Key to match by vehicle.
Texas Instruments fixed-code
A first-generation fixed-code transponder from Texas Instruments, found in Toyota, Lexus and Ford keys from the mid-1990s through the early 2000s. It transmits the same identification code on every read, with no cryptographic challenge, which makes it straightforward to clone onto an aftermarket clone chip. It was superseded by the encrypted 4D family.
DST40
A Texas Instruments crypto transponder family built on the 40-bit DST (Digital Signature Transponder) algorithm. The immobilizer issues a random challenge and the chip must return the correct encrypted response, so a 4D key cannot be copied by reading a fixed code alone. Variants such as 4D-60, 4D-63 and 4D-67 carry manufacturer-specific configurations — Ford, Ford/Mazda and Toyota respectively.
Spare key programming
A programming job where at least one working key is present and a spare is being registered alongside it. Because the vehicle can authenticate the existing key, most platforms allow add-a-key through a simplified procedure — on some, an onboard procedure with no diagnostic tool at all. It is the faster, lower-risk counterpart to an all-keys-lost job.
A new key or remote produced by a third-party manufacturer to match the fit, frequency, transponder type and function of the part it replaces, rather than by the vehicle maker. Quality aftermarket keys are matched to the original through the FCC ID, part number and cross-reference data, so fit is verified before the part ships. The Car Key Source catalog is 100% new aftermarket stock, sold wholesale to the trade.
AKL
A job where no working key exists for the vehicle. With nothing to authenticate against, the immobilizer must be reached another way — an OBD procedure with a PIN code, a forced key-learn that wipes the stored keys, or EEPROM work on the module itself. AKL jobs take longer, carry more risk and command higher rates than add-a-key work.
Coin-cell batteries
The two 3-volt lithium coin cells that power most key fobs. The four digits encode the size — a CR2032 is 20 mm across and 3.2 mm thick, a CR2450 is 24.5 mm across and 5.0 mm thick — so the two are not interchangeable. A fresh cell is the first diagnostic step for weak range or an intermittent remote; the transponder itself needs no battery at all.
A documented equivalence between part identifiers — which OE part numbers, aftermarket numbers and FCC IDs describe interchangeable parts. One remote design commonly ships under many numbers across model years and trim levels, so cross-reference data is how a supplier confirms that the part on the shelf replaces the part in the customer's hand.
80-bit DST · Toyota G chip
Texas Instruments' 80-bit successor to the 40-bit DST algorithm, introduced after published attacks showed the original key length was too short. Its best-known applications are Toyota's G chip (stamped "G" on the blade, roughly 2010–2014) and Ford's 80-bit PATS keys of the same era.
Toyota H chip · 8A
The current Texas Instruments transponder generation, which replaces the proprietary DST cipher with 128-bit AES. Toyota's H chip — commonly cataloged as 8A — is the flagship application, appearing on Toyota and Lexus bladed keys from around 2013 onward, and the same silicon family sits inside many late-model smart keys.
Standard cut
A key whose bitting is cut into the edge of the blade as a row of angled peaks and valleys — the traditional cut that any basic duplicator handles. It contrasts with the laser-cut (sidewinder) style, where the pattern is milled as a groove into the face of a thicker blade. Older domestic platforms and many economy vehicles still use edge cuts.
Electrically erasable programmable read-only memory — the non-volatile chip inside immobilizer modules and body control modules that stores key data, PINs and configuration. In the trade, "EEPROM work" means reading that chip directly, typically in an all-keys-lost job where no OBD route exists. It demands soldering skill and the right adapters, and it is the deepest tier of key programming.
Valet blade
The small mechanical blade tucked inside a smart key or fobik, released by a catch, that opens the driver's door when the fob battery — or the vehicle battery — is dead. On many platforms it is the only mechanical path into the car. When quoting a smart key job, remember the emergency blade still has to be cut to the vehicle's bitting.
The identifier the Federal Communications Commission assigns when a radio-transmitting device is certified for sale in the United States — printed on virtually every key fob's case or circuit board. Because the ID is tied to the exact transmitter hardware, it is the single most reliable way to match a replacement remote: same FCC ID, same radio. It is not a part number, though — one FCC ID can cover several part numbers with different button counts or blades, so confirm both before ordering.
Switchblade key
A remote key whose blade folds into the body and springs out at the press of a button, a design popularized by Volkswagen in the 1990s and since used across many makes. The blade and the remote electronics are serviceable separately on most designs, which makes flip keys strong candidates for shell replacement rather than full replacement.
A blade-less, plastic-bodied key used by Chrysler, Dodge, Jeep and Ram from roughly 2008 into the mid-2010s, inserted into a dash-mounted receptacle — the WIN, or Wireless Ignition Node — and twisted like a conventional key. It carries the transponder and remote electronics in one housing, plus an emergency blade for the door. Fobiks are their own product category: neither a bladed remote head key nor a true proximity fob.
315 / 433 / 902 MHz
The radio carrier a key fob transmits on — 315 MHz, 433 MHz or 902 MHz in the North American market. North American vehicles historically used 315 MHz; 433.92 MHz — long the standard in Europe — is now common on newer North American platforms as well; and some late-model vehicles, notably recent Fords, use 902 MHz for two-way remotes. Frequency must match exactly: a 315 MHz remote will never program to a 433 MHz receiver, no matter how identical the shells look.
ISED / Industry Canada number
The Canadian counterpart to the FCC ID, issued under the radio certification rules of Innovation, Science and Economic Development Canada (formerly Industry Canada). It is usually printed alongside the FCC ID on the fob's label or board, and devices sold in both markets carry both identifiers. Either one can be used to match a replacement remote.
PCF7936 · Hitag 2
An NXP (Philips) crypto transponder built on the Hitag2 cipher — one of the most widely deployed immobilizer chips ever made. GM, Chrysler, Honda, Nissan, Hyundai, Kia and many European makes used ID46-family silicon through the 2000s and 2010s, both as the standalone PCF7936 transponder and embedded inside remote ICs such as the PCF7941 and PCF7961. "ID46" is the designation tools report; PCF7936 is NXP's part name for the bare transponder.
HITAG 3
An NXP transponder generation based on the Hitag3 platform, which replaced Hitag2 with stronger authentication after Hitag2's cipher was publicly broken. It is best known in Honda keys from around 2014 onward and in a range of Hyundai and Kia applications. Like all such designations, "ID47" describes what a cloning or diagnostic tool reports rather than one physical part.
HITAG Pro
An NXP transponder generation built on the Hitag Pro platform with 128-bit AES authentication. Ford adopted it across its 2015-and-newer smart key and bladed-key platforms, and Mazda uses it in keys of the same era. Tools report it as ID49.
HITAG AES
NXP's newest mainstream transponder designation, built on the Hitag AES platform. It appears in late-model Hyundai and Kia keys among others, and it is steadily displacing the older ID46/ID47 families as platforms turn over. Cloning ID4A requires current-generation chips and up-to-date tool firmware — older clone chips cannot emulate it.
The vehicle's electronic anti-theft system: an antenna coil around the ignition (or the cabin's LF antennas) interrogates the key's transponder, and the engine is allowed to run only when the correct cryptographic response comes back. Immobilizers are why a mechanically perfect copy of a modern key will crank the engine but not start it. Key programming is, at bottom, teaching the immobilizer to trust a new transponder.
An uncut key, ready for the bitting to be cut to a specific vehicle. A blank may be bare metal for older vehicles or carry a transponder for immobilizer-equipped ones, and it is identified by its keyway profile plus the chip it carries. Stocking the right blanks by keyway is what lets a shop cut on demand.
The equipment that cuts a blank to a vehicle's bitting. Duplicators trace an existing key; code machines cut from the factory key code or from depths decoded with a Lishi tool; and milling machines with rotary cutters handle high-security laser-cut blades. Cutting is only half of a modern key job — the transponder or remote still has to be programmed.
The process of registering a new key, transponder or remote with a vehicle so the immobilizer and the remote receiver accept it. Depending on the platform this happens through an onboard procedure, a diagnostic tool on the OBD-II port, or module-level EEPROM work. Programming is separate from cutting: most modern key jobs require both.
A replacement case — buttons, housing and often the blade — with no electronics inside. Moving the customer's board, transponder and battery into a new shell restores a cracked or worn key without any programming, because the electronics never change. Shell replacement is a fast, low-risk repair every automotive locksmith should offer.
The cross-sectional profile of a key blade — the pattern of grooves that lets it enter one lock cylinder family and no other. Keyways are named by standardized references such as TOY43 (Toyota), HON66 (Honda) and HU100 (GM high-security). The keyway determines which blank, which Lishi tool and which cutting setup a job needs.
Sidewinder · high-security key
A key whose bitting is milled as a winding groove down the face of a thicker blade, rather than cut into the edge. Despite the name, no laser is involved — the pattern is cut with a rotary milling bit on a dedicated machine. Laser-cut systems offer tighter tolerances and harder-to-duplicate blades, and they are standard equipment on most late-model vehicles.
A keyway-specific two-in-one tool, named for its inventor Li Zhi Qin, that both picks a lock open and decodes the depth of each cut. Reading the cuts off a door lock with a Lishi lets a locksmith cut a working blade by code without disassembling anything. Each keyway needs its own Lishi, so a working kit is built around the keyways in the local vehicle population.
The standardized 16-pin diagnostic connector required on gasoline vehicles sold in the United States since 1996, almost always found under the driver's side of the dash. Key programmers connect here to communicate with the immobilizer and body control module. "OBD programming" distinguishes this tool-based work from onboard procedures on one side and bench or EEPROM work on the other.
OE number
The vehicle manufacturer's own catalog number for a component — for keys, a string such as GM's 13529633, printed in the parts catalog and often on the fob's label. In the key trade the OE number works as a universal reference point: aftermarket keys are cataloged against the OE number of the part they replace, so matching the number on the customer's original confirms fit even when the replacement is not a factory part. Car Key Source stocks aftermarket equivalents matched by these numbers, listed alongside the FCC ID and cross-reference data on every product.
A key-learning procedure performed with the vehicle's own controls — sequences of ignition cycles, door-lock presses or button holds — rather than a diagnostic tool. It remains available for add-a-key on some current platforms and was common on older domestic ones. Availability is strictly platform-specific: many modern vehicles have no onboard procedure at all.
Proximity key · passive entry passive start
Passive Entry, Passive Start — the architecture behind push-button-start vehicles. Low-frequency antennas in the cabin and door handles challenge the fob, the fob answers over UHF, and the vehicle unlocks and starts while the key stays in a pocket. A PEPS fob is a different product class from a button-press RKE remote: it has to handle the LF/UHF handshake, not just transmit on demand.
Security code
A code the immobilizer demands before it will enter key-programming mode — standard on Nissan, Hyundai, Kia, the Chrysler family and many European platforms. Depending on the make, the PIN is calculated from vehicle data, pulled from a module by the diagnostic tool, obtained through authorized dealer or NASTF channels, or recovered via EEPROM work. No PIN, no programming, on the platforms that require one.
A used original fob that has been recovered, tested and often recased for resale. On many platforms a used fob locks to the first vehicle it was programmed to, so refurbished units must be unlocked or renewed with the right tooling before they can be programmed again. It is a distinct category from aftermarket: a refurbished key is used original hardware, while an aftermarket key is newly manufactured — know which one a listing is before you quote a job on it.
RHK
A one-piece key with the remote buttons built into the plastic head above a fixed blade, so the transponder and RKE electronics share one housing. It was the dominant key style on 2000s and early-2010s vehicles, before proximity fobs took over the mid-market. Remote head keys still make up a large share of daily locksmith work.
Remote keyless entry
The button-press remote system — lock, unlock, panic, trunk — carried by a fob or key head and received by the vehicle over UHF. RKE handles convenience functions only; starting the engine is the immobilizer's domain. That split is why a remote can work perfectly while the vehicle still refuses to start, and vice versa.
Hopping code
The anti-replay scheme used by vehicle remotes: fob and receiver share a synchronized code sequence, and every button press transmits a fresh code that is never valid twice. An intercepted transmission is therefore useless for a simple replay attack. Rolling code is also why remotes must be programmed — synchronized — to the vehicle rather than simply set to a matching frequency.
The trade and consumer term for a PEPS proximity fob — the blade-less fob that unlocks and starts the vehicle from a pocket. In catalogs, "smart key" distinguishes proximity fobs from RKE-only remotes and bladed keys. Almost every smart key hides an emergency blade for the driver's door.
A passive RFID chip embedded in the key head that answers the immobilizer's challenge. It is powered by the electromagnetic field of the antenna coil around the ignition — or by the vehicle's LF antennas — so it needs no battery: a key with a dead remote battery still starts the car on most bladed-key platforms. Chip families such as 4C, 4D, ID46 and ID47 differ by manufacturer and cipher, and the right family is as critical to fit as the right blade.
PassKey · resistor key
GM's Vehicle Anti-Theft System, used from 1986 into the early 2000s: a resistor pellet in the key blade, in one of 15 factory resistance values, is measured by the ignition circuit before the car will start. VATS predates transponders — there is no chip and nothing to program — but the replacement key must carry the correct resistance value. Decoding the pellet value is part of any service call on these vehicles.
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