Principle and Function of LTE Modem

LTE Modem is used to transmit data, and most of the LTE modems on the market are two-way transparent transmissions. For example, if the collected signal is 01010101, then the data it transmits is 01010101.

Origin of LTE Modem

LTE Modem was originally a combination of the words modulator and demodulator, and its transmission form is the transmission of encoded digital information. At that time, the transmission was carried out within the frequency range of the standard telephone line, transmitted to another LTE Modem through the telephone channel, and decoded on the receiving LTE Modem.

As early as the 1920s, there was a product called LTE Modem. In the 1940s, LTE Modem was used on typewriters. At that time, the transmission speed of the LTE Modem was 25 bytes per second. By 1958, LTE Modem was used in the military and was called Smart LTE Modem.

With the advent of wireless cellular networks, LTE modems were later developed to be wireless and transmitted through 4G networks, so they were called 4G LTE modems. Around 1990, there were domestic manufacturers in R & D and production.

With the continuous development of science and technology, there are 3G, 4G, and NB-IoT networks, as well as LTE Modem and NB-IOT LTE Modem. Subsequently, due to the maturity of short-distance communication technologies such as LoRa, WiFi, and Bluetooth, LoRa LTE Modem, WiFi LTE Modems, and Bluetooth modules have also appeared.

Basic functions of LTE Modem

No matter what functions LTE Modem has, it can not do without these four basic functions. These four are the most basic, but also must-haves!

(1) Internal integration of TCP/IP protocol stack

There are external protocol stacks and built-in protocol stacks, and most of them are external protocol stacks on the market. TCP/IP protocol stack can be understood as the combination of a wireless modem and an embedded PC. It allows LTE Modem to have dial-up Internet access and TCP/IP data communication functions.

(2) bidirectional conversion of serial port data

Support the conversion of RS232, RS485, RS422, and other common serial ports into TCP/IP data for transmission. Since it is two-way transparent transmission, TCP/IP data can also be converted into the above common serial ports.

(3) Support custom heartbeat package

One of the advantages of the 4G communication network is it supports the terminal equipment to be always online, so a typical LTE Modem is designed to support the always online function. This requires the LTE Modem to include power-on auto-dial and heartbeat packets to keep it permanently online (when there is no data for a long time).

(4) Parameter configuration and permanent storage

In different applications, the IP address, port number and baud rate of the serial port in the data center are different. This feature allows the LTE Modem terminal device to support parameter configuration, and the configured parameters can be stored permanently, mainly in the internal permanent storage device, such as the common FLASH or EEPROM. After the user turns on, the LTE Modem will work automatically according to the set parameters.

Application of LTE Modem

Take LTE Modem as an example, in some commercial buildings and industrial plants. Meter reading has been a headache in the past, especially in commercial buildings, meter reading is the responsibility of the property. Manual meter reading is time-consuming and laborious, so after the development of the Internet of Things, LTE Modem combined with smart meters can solve this problem well.In a distribution box, an LTE Modem can be installed to add a collector, which can collect data from many meters. And transmit that data to the management platform. It is convenient for the property to check the electricity consumption of each meter and charge according to its electricity consumption.