English abbreviation ICD, the full name of the Industrial Communication Device. wired communication devices are mainly industrial field serial communication, professional bus type communication, industrial Ethernet communication and various communication protocols between the conversion device. Wireless communication devices are mainly wireless AP, wireless bridge, wireless card, wireless lightning arrester, antenna and other equipment.
Wi-Fi communication equipment ?WirelessFidelity, wireless fidelity: is used in the office and home in the short-range wireless technology. The technology uses the frequency band around 2.4GHz, which is currently an unlicensed wireless band. There are two standards available, IEEE802.11a and IEEE802.11b. The so-called WiFi communication devices should refer to the communication devices that support this technology.
The theory of electromagnetic waves was created by Maxwell, and it was the Italian Marconi who invented the telegraph communication equipment based on electromagnetic waves, while Bell was the one who invented the telephone．
Wireless communication is the use of radio waves rather than cables to achieve communication between the equipment, this communication method has a fast and simple installation and maintenance, not affected by the site terrain environment, the cost is not a high advantage, a wealth of products to meet the user in the communication distance and communication rate of different needs.