RS-485/Modbus is a popular way of network layout, which is characterized by simple and convenient implementation. The RS485 conversion interface is relatively cheap and has a wide variety of types.

IoT gateways will also become an important link for connectivity. As a gateway device, in addition to being responsible for the protocol conversion between different types of perception networks, the IoT gateway can integrate the information collected by different things and transmit it to the next level, so that the information can be Transmission between the various parts. The IoT gateway can re···

The Modbus protocol includes ASCII, RTU, TCP, etc., and does not specify the physical layer. This protocol defines the message structure that the controller can recognize and use, regardless of what kind of network they communicate through. The standard Modicon controller uses RS232C to implement serial Modbus.

The wireless communication module enables all kinds of Internet of Things terminal devices to have the ability to transmit information on the Internet, and is the information portal for all kinds of intelligent terminals to access the Internet of Things. At present, in the M2M scenario, more cellular communication modules (2G/3G/4G) are used. In the future, LPWAN modules (NB/IoT, LoRa) will be rap···

2.4G and 5G are different protocols used by wireless networks. 2.4G refers to 2412MHZ-2472MHZ in the country, which can be divided into 13 full channels, while 11 channels are regulated in the United States. 5G is 5725MHZ~5825MHZ in this country, 4 channels.

When the distance to the router is the same, the 5G signal is weaker than the 2.4G signal, which is determined by the physical characteristics of electromagnetic waves: the longer the wavelength, the less attenuation, and it is easier to bypass obstacles and continue to spread. The 5G signal has a high frequency and short wavelength, while the 2.4G signal has a low frequency and a long wavelength.···

Spread Spectrum Communication, that is, spread spectrum communication technology (Spread Spectrum Communication), its basic characteristic is that the bandwidth of the signal used to transmit information is much larger than the bandwidth of the information itself.

M2M (Machine to Machine) is a machine-to-machine communication technology, in a broad sense, M2M (Man to Machine), the Internet of Things is to connect objects (including machines) together. Obviously, M2M is an important part of the Internet of Things to connect objects. It is impossible to connect objects to form a huge Internet of Things without M2M technology. M2M technology and products are i···

The wireless communication module is a key link connecting the perception layer and the network layer of the Internet of Things. It belongs to the underlying hardware link and is irreplaceable. There is a one-to-one correspondence between the wireless communication module and the Internet of Things terminal.

DTU is the full name of GPRS data transmission unit. At present, there is actually a clearer agreement on GPRS DTU in China: GPRS DTU is a GPRS wireless device specially used to transmit serial port data through GPRS network.