(1) transmitter launcher is commonly known as "remote control", which consists of a password generator, a key input circuit, a wireless transmitter circuit, and a working frequency of 256 to 320MHz, and a frequency of 315 to 318MHz. The pool can support a remote control operation of about 5000 times. The effective operation range of the early production remote control is only 5 ~ 10m, the distance of the remote control of most models is 10-15m, the distance of the remote control of a few models reaches 30 ~ 50m. The remote control signal is transmitted by infrared, radio or ultrasonic waves, mostly in two ways, infrared and radio waves. In order to be portable, the modern car's remote control is integrated with the ignition key, which is made into a handheld micro key button, so it is also called "key" and "anti-theft key". In the remote controller's handle, it contains chips with specific passwords or resistors. The remote controller is the carrier of the output of the anti-theft code. It is an important part of the electronic anti-theft system. It is connected with the main control circuit by means of magnetism and electricity. The function of the remote controller is actually to launch radio frequency signal to control the action of the burglar alarm. When the function key of the remote controller is pressed, the function code (fixed code) and identity identification code (variable code) in the chip read-out memory are converted to the controlled signal of infrared or radio wave, in which the infrared pulse is modulated to drive the light emitting diode and the radio wave is modulated into high frequency. Signal, and then send out. According to the setting and launching mode of the password, the car electronic security system is divided into two kinds: one is the code of fixed code, such as the password of the one, Beos, the iron general and so on; the other is the rolling code, such as the cipher of the anti-theft device such as the warlord and the eagle guard. The security system of BMW cars and Santana 2000GS1 adopts rolling codes. For these models, each time the remote control is unlocked or started, the random code generator in the anti-theft control module sends a hopping signal to the central control door lock controller on the car, and both the transmitter and the receiver jump a number at the same pace. This combination of password has hundreds of millions of kinds, can improve the reliability of anti-theft. If the signal of the transmitter and receiver is not uniform due to some reason, the engine can not start. At present, there are many car burglar devices called "jump code", "code change", "global code", but only some of them are real jumping code (roll code), and the rest are the fixed - type anti-theft devices for changing packaging. The following is a simple method for identifying "code" and "jump code": hold down a function key 30s of the remote control, if the emission indicator on the remote control is extinguished (indicating that the remote control stops working), the anti-theft device is a skip code type, otherwise it is a fixed code type anti-theft device. Generally speaking, the code hopping anti-theft device is integrated design, and the anti-theft control module can learn the remote controller, so the price is relatively high.