What do you mean by GSM?

GSM stands for Global System for Mobile Communications, which is a standard developed to describe the protocols for second-generation (2G) digital cellular networks. It enables mobile phones to communicate with each other and with the network, providing services like voice calls, SMS, and data transfer. GSM is widely used around the world and has evolved to support various technologies, including 3G and 4G, while remaining foundational for mobile communication.