A GSM/GPRS modem is a device used to establish communication between two computers using the GSM-GPRS system. Global System for Mobile communication (GSM) is an architecture used for mobile communication in most of the countries. On the other hand, General Packet Radio Service (GPRS) is an extension of GSM that enables higher data transmission rate. Usually, these devices are assembled together with power supply circuit and communication interfaces such as RS-232, USB, and so on.
In order to work, these devices require a subscriber identity module (SIM) card just like mobile phones to activate communication with the network, and once the SIM is inserted, they can perform the following main operations: