From the current technical level and market recognition level, the most widely used is the keyboard type electronic code lock. The keyboard type electronic password is input on the keyboard, which is similar to the telephone call, so it is easy to grasp. The outstanding advantage is that the "password" is a number or character recorded in the mind of the authorized person. It is accurate and reliable, will not be lost (except forgotten), and is difficult to be stolen (unless it is leaked by itself). If the password is leaked, the password lock will be ineffective.