In the field of communication and network, the meaning of bandwidth is different from the above definition. It refers to the difference between the highest frequency and the lowest frequency that can be used by network signals, or the "width of frequency band", that is, the so-called "Bandwidth" and "channel bandwidth", which is also the most rigorous technical definition.
In copper medium cabling systems such as 100m Ethernet, the channel bandwidth of twisted-pair is usually measured in MHz, which refers to the allowable channel frequency range under the condition of constant signal-to-noise ratio. However, there is a stable basic relationship between the channel bandwidth of a network and its data transmission capacity (unit: Byte/s).We can also use the highway as an analogy: on the highway, the maximum traffic flow it can bear is equivalent to the data transportation capacity of the network, and the width allowed by the highway is equivalent to the bandwidth of the network.Obviously, the higher the bandwidth, the more resources are available for data transmission, and thus the higher the speed can be achieved. In addition, we can achieve higher transmission speeds by improving signal quality and eliminating bottlenecks.
Baseband transmission:
The frequency spectrum of a digital signal generated by a computer or terminal starts from zero. The frequency range occupied by this unmodulated signal is called the base band (this frequency band can be as high as hundreds of kilohertz or even several megahertz from DC), or the base band for short. This digital signal is called a baseband signal.To take a simple example, in a wired channel, the signal transmitted when communicating directly with a teletypewriter is the baseband signal. When data is transmitted, the baseband signal is sent to the line in its original form, which is called baseband transmission.Baseband transmission does not require a modem, the cost of equipment is low, and it is suitable for short-distance data transmission. For example, an enterprise or factory can connect a large number of terminals to a host computer in this way. The other is the transmission medium. Baseband coaxial cable is generally used as the transmission medium in the LAN.
Band transmission:
The above transmission mode is applicable to the local area network transmission within a unit, but except for local lines, long-distance lines cannot transmit components similar to 0, that is to say, in the long-distance communication of computers, the original electrical pulse signals (that is, baseband signals) cannot be directly transmitted.Therefore, it is necessary to use frequency band transmission, that is, to use baseband pulses to control some parameters of the carrier waveform, so that these parameters change with the baseband pulses, which is modulation. A modulated signal is called a modulated signal. The modulated signal is transmitted over the wire to the receiving end and then demodulated back to the original baseband pulse.This kind of frequency band transmission not only overcomes the shortcoming that many long-distance telephone lines can not directly transmit baseband signals, but also realizes the purpose of multiplexing, thus improving the utilization rate of communication lines. However, band transmission requires modems at both the sending and receiving ends.
Lte cat 4 modem application diagram
Lte cat 4 modem, abbreviated from Data Terminal unit, literally translated as data transmission unit, is a wireless terminal device specially used to convert serial port data into IP data or convert IP data into serial port data for transmission through wireless communication network. It is one of the M2m transmission devices of the Internet of Things, and its application scenarios mainly include transparent data transmission.
Through monitoring, measure the sensors and devices installed at remote sites, and be responsible for signal transmission. But also can carry out that "four remote" functions of remote measurement, remote control, remote signal and remote regulation on the field equipment through the own software system. The main applications are hydrology and water conservancy, temperature and humidity monitoring, heating network monitoring, gas monitoring, environmental protection detection, meteorological monitoring, traffic control and other industries.
Basic functions
1) Data communication: Lte cat 4 modem internally integrates TCP/IP protocol stack and supports Modbus RTU to Modbus TCP; The public Cat-1/GPRS/4G wireless network is used to provide users with wireless long-distance stable and reliable short message and data transmission functions. Support SMS and data transmission; AT Command is supported.
2) Data acquisition: collect data of serial equipment, such as serial instrument, collector, PLC, SCADA, etc.
3) Support permanent online: Lte cat 4 modem includes multiple online modes such as digital displacement trigger or pulse counting event trigger, timer trigger, voice incoming trigger and SMS trigger; Built-in powerful timer function, supporting timing automatic reporting, timing online, timing offline, timing restart and other functions; The device supports always online.
4) Support master-slave: Support master-slave servers, which can be DNS or IP addresses.
5) Remote management: support remote SMS to restart the device and configure device parameters; Support remote program upgrade and remote SMS configuration parameter query.
6) Programmable: powerful programmable function, support custom handshake protocol, heartbeat packet content and offline protocol.
7) Support USB: support USB interface for parameter configuration, reading, data monitoring, AT instruction and program upgrade through computer configuration software;
Lte cat 4 modem (Data Transfer unit) is a wireless terminal device specially used to convert serial port data into IP data or convert IP data into serial port data for transmission through a wireless communication network. Lte cat 4 modem is widely used in meteorology, hydrology, water conservancy, geology and other industries.
Lte cat 4 modem (Data Transfer unit) is a wireless terminal device specially used to convert serial port data into IP data or convert IP data into serial port data for transmission through a wireless communication network.
How the Lte cat 4 modem works:
The most basic usage of the Lte cat 4 modem is: put a SIM card with 4G function in the Lte cat 4 modem, register to the 4G network after powering on the modem, and then establish a connection with the data processing center through the 4G network.
This connection involves the wireless network operator, the Internet broadband provider, the network situation of the user's company, and the user's computer configuration, so to establish this connection, all parts need to be configured. Essentially, the Lte cat 4 modem establishes a SOCKET connection with the data processing center.Lte cat 4 modem is the client of SOCKET, and data processing center is the server of SOCKET.
The SOCKET connection is divided into TCP protocol and UDP protocol. Lte cat 4 modem and the center should use the same protocol, which is generally configured by configuration software. After the IP address and port number of the center are configured for the Lte cat 4 modem, the Lte cat 4 modem is connected to the user's device through the serial port.
Lte cat 4 modem is connected with hydrology, power, meteorology, environmental protection and other equipment and placed on site. After the Lte cat 4 modem is powered on, it first registers to the mobile network, then sends a request packet to establish SOCKET to the mobile, and the mobile sends this request to the Internet. After receiving the request, the server software of the center establishes a connection and sends a response message.
The request information sent by the Lte cat 4 modem is a data packet on the Internet, and there are some reasons that prevent the center from receiving the connection request packet, so that the connection cannot be established. The most common is that there are anti-virus software, firewalls and so on on the central computer to shield these data packets. The other is that the central computer accesses the Internet through the router, and data forwarding should be set up on the router.After the SOCKET connection is established, two-way communication is possible.
Industrial Lte cat 4 modem (data transmission unit) and Industrial Lte 4G router are two kinds of devices commonly used in the industrial field, which have different functions and application scenarios.
Industrial Lte cat 4 modem is a device specially designed for data communication and remote monitoring. It is usually used to connect sensors, instruments or automation systems to remote servers or cloud platforms to achieve data acquisition, transmission and management.Industrial Lte cat 4 modem has the functions of data acquisition, signal conversion, data compression, protocol conversion and data transmission, and can transmit the data of field devices to the background system for analysis and processing through various communication methods (such as 2G/3G/4G, Wi-Fi, Ethernet, etc.).
The Industrial Lte 4G router is a device designed to set up and manage Industrial networks. It plays a key role in network communication and data transmission in the field Industrial environment. The Industrial Lte 4G router has multiple network interfaces and is capable of connecting to different network devices and systems, including sensors, PLCs (programmable logic controllers), human-machine interfaces, etc.In the Industrial scenario, the Industrial Lte 4G router can be used to realize communication and interconnection between different areas or devices, and transmit control signals, monitoring data and alarm information through the network.
The differences between the Industrial Lte cat 4 modem and the Industrial Lte 4G router can be briefly summarized as follows:
1. Function: Industrial Lte cat 4 modem is used for data acquisition, compression and remote transmission; Industrial Lte 4G router is used for establishing and managing Industrial network.
2. Application: Industrial Lte cat 4 modem is mainly used for data communication and remote monitoring; Industrial Lte 4G router is mainly used for network communication and data transmission.
3. Interface and protocol: Industrial Lte cat 4 modem usually supports multiple communication modes, such as 2G/3G/4G, Wi-Fi, Ethernet, etc. Industrial Lte 4G router has multiple network interfaces and supports different communication protocols.
4. Device connection: Industrial Lte cat 4 modem is mainly connected with sensors, devices or automation systems; Industrial Lte 4G router is mainly connected with network devices and systems.
It should be noted that Industrial Lte cat 4 modem and Industrial Lte 4G router can also be used simultaneously in some application scenarios to implement more complex Industrial IoT solutions.
There are several factors to consider when selecting an Industrial Lte cat 4 modem or Industrial Lte 4G router:
1. Functional requirements: First of all, you need to clarify your specific requirements. Industrial Lte cat 4 modem is a suitable choice if you need to realize remote data acquisition and transmission, and data interaction and management with the background system.If you need to set up and manage network communication at the Industrial site to connect different devices together, then the Industrial Lte 4G router is more suitable.
2. How data is transmitted: Consider your site environment and available network services. If you have an existing network connection, such as 2G/3G/4G, Wi-Fi or Ethernet, the Industrial Lte cat 4 modem can choose the appropriate communication method according to your communication needs.The Industrial Lte 4G router is required if you need to set up a LAN or Wan to support communication between devices.
3. Device interface and protocol: Verify that your device has an Industrial Lte cat 4 modem or Industrial Lte 4G router compatible interface and communication protocol. Choose the equipment that matches your equipment and system to ensure smooth data transfer and communication.
4. Strength and reliability: In the Industrial environment, stability and immunity are important. Ensure that the optional Industrial Lte cat 4 modem or Industrial Lte 4G router has strong anti-interference capability and can maintain stable communication in harsh environments.
5. Expansion and compatibility: Consider future development needs and compatibility. Select equipment that can support expansion and more interfaces to meet possible future changes in demand.
To sum up, the choice of Industrial Lte cat 4 modem or Industrial Lte 4G router depends on the specific needs and environment. Assessing your data acquisition and communication requirements, as well as device and system compatibility, can help you make the right choice.
