The car door lock was introduced soon after the first car was stolen and it was then the best technology for the job. The standard still remains the same that is the simple lock and key. But fumbling with keys all the time creates nuisance especially with stuff like groceries in hand. This aides the necessity of remote controls for cars, and this is primarily why the remote car door opener have been in action since 1980s.
The remote controls for car are of higher range and use infrared beams. So the manufacturers use flexible and higher range frequency controllers for the same. Because of the risk that thieves pose these need higher security than any television remote. They have always been dependent on codes that tend to keep away the thieves. Earlier the working was complex, the transmitter in the remote system used to send identification codes that were programmed into the receiver. This code would only work if the receiver intended for it. That’s why more workables code systems came into action in the mid of 1990s. Now instead of using fixed identification codes, rolling codes came into play which changed with every press. The stored codes at the transmitter’s end matched the stored data at the receiver’s end.
If understood theoretically then these code grabbers could figure out basic rolling codes by their own and the next in sequence too. But this system was thwarted much by the system of rolling codes. Since the key which resides in the receiver where no transmission occurs, a car would in this case need access to the transmitter to crack the code. But at this stage the thief would not need it and we would need car key remote replacement.
They have now moved from luxury options to a standard security system, which leads to further development too. Receiver are now built for multiple functions, which lowers the cost of keyless systems. They are continuously adding more antitheft and immobilizing systems causing the original replacement car remotes. These immobilizers use low frequency signals to carry codes. Once you press the correct code, it hinders the fuel pump operation and so the engine runs out of the fuel pump at some distance.
These systems however differ from remote keyless once. They have a shorter range and compared to keyless systems and the car sends off the challenger number which the controller returns with its code.
Despite such difference, these together form the basics of new typology of vehicles. These remote keyless systems have become more sophisticated over the decade and the newest ones start a car without a key, thus the need of car remote replacement has increased. The transmitters are usually fitted with an integrated circuit powered by lithium battery and buttons to activate contact switches. The receiver on the other hand picks up the code by the transmitter. If the code matches the information is passed on to the processor. The processor then forwards the signals to the door, triggering actuators which is connected to latches.
For more info: Nissan keyless remotes