Electrostatics is an objective natural phenomenon, which is the positive or negative charge formed by the charge imbalance caused by contact, friction or induction on the surface of an object. It is characterized by long time accumulation, high voltage, low electric quantity, small current and short action time. In the manufacturing process of the product, static electricity will bring us unexpected trouble and trouble, the ESD (Electrostatic Discharge) is the electrostatic discharge caused by the biggest harm, relative to other industries, with the miniaturization and highly integrated, together with the use of a large number of MOS process, caused by electrostatic discharge (ESD) circuit or components failure events increasing.

A modem is a device capable of modulating a digital signal at the transmitting end, converting it into an analog signal, and demodulating the analog signal at the receiving end to reconvert it into a digital signal. It builds a key bridge between digital communication and analog communication, effectively solves the problem of mutual conversion and transmission between different signal types, to adapt to the requirements of different transmission media and communication networks, and ensure that data can be accurately and stably transmitted and interactive in various communication links.