GPRS modem adopts high-performance industrial-grade 8/16/32-bit communication processor and industrial wireless module. It is supported by an embedded real-time operating system and provides RS232 and RS485(or RS422) interfaces. It can directly connect to the serial device server and realize transparent data transmission.
Today let’s have a look at the functions of GPRS modem:
1) internal integration of TCP/IP protocol stack
GPRS modem encapsulates PPP dial protocol and TCP/IP protocol stack and has an embedded operating system. In terms of hardware, it can be regarded as the combination of embedded PC and wireless GPRS MODEM. It has GPRS dial-up Internet access and TCP/IP data communication functions.
2) provide bidirectional transmission function of serial port data.
GPRS modem provides serial communication interface(SCI), including RS232 and RS485, RS422, etc which are the commonly used serial communication mode, and the serial data mostly on the design of GPRS MODEM design into a “transparent conversion” approach, that is to say, GPRS MODEM can transform a serial port on the original data into TCP/IP packet transmission, and don’t need to change the original data communication content. Therefore, GPRS MODEM can be connected with various user devices that use serial port communication, and there is no need to modify the user devices.
3) Support automatic heartbeat and keep it online forever
one of the advantages of GPRS communication network is support GPRS terminal equipment permanently online, so all the GPRS modem is designed with permanently online function, which requires the modem support network heartbeat package and serial port heartbeat package. Network heartbeat packets keep the server active by sending heartbeat packets continuously to maintain a normal connection with the server.
The serial heartbeat packet keeps the serial device in an active state and actively grabs the sensor data that cannot be pushed actively.
4) support parameter configuration and permanent storage
As a communication device, GPRS MODEM is widely used in different applications, data center IP address and port number, serial port baud rate are different. Therefore, GPRS modems should support parameter configuration and store the configured parameters in internal permanent storage devices (generally FLASH or EEPROM, etc.). Once the power is on, it will work automatically according to the set parameters.
5) support serial port parameter setting
The serial port parameters of different user devices are different. When modem connects to the serial port of user devices, the modem should be set according to the actual parameters of the serial port of user devices to ensure the normal communication and reliable data transmission of user devices.