CMIIT ID is the radio transmitting equipment type approval code.
With a CMIIT ID, a cell phone can transmit wireless signals such as GSM, EDGE, WCDMA, Bluetooth, WIFI, NFC, and so on. Radio transmitting equipment is defined as all kinds of equipment that emits radio waves, but does not include industrial, scientific research, medical equipment, electrified transportation systems, high-voltage power lines and other electrical devices that can radiate electromagnetic waves.
According to the relevant provisions of the production, imported radio transmitting equipment, are required to transmit the characteristics of its type approval, the issuance of "radio transmitting equipment type approval certificate" and the type approval code, the factory equipment shall be marked on the label type approval code. In layman's terms, only with our radio transmitting equipment type approval code of radio transmitting equipment, radio transmitting equipment can be sold and used in China.
Radio applications
Radio was first used in navigation, the use of Morse Telegraph in the ship and land between the transmission of information. Radio has many applications, including wireless data networks, various mobile communications, and radio broadcasting. The earliest form of broadcasting was marine radiotelegraphy. It used switches to control the emission or non-emission of continuous waves, and the resulting signal, known as Morse code, was generated at the receiver.
Radios for government, fire, police, and commercial use typically apply narrowband FM technology in specialized frequency bands. These applications typically use a bandwidth of 5 KHz. Relative to the bandwidth of FM radio or television, sacrifices have to be made in fidelity. Civilian or military HF services use shortwave for communications between ships, aircraft or isolated locations. In most cases, single-sideband technology is used, which saves half the bandwidth compared to AM technology and utilizes the transmit power more efficiently.