GSMn
GSMn refers to a specific version or implementation of the Global System for Mobile Communications (GSM) standard. GSM is a globally used standard for digital mobile telecommunications. It was first introduced in Finland in 1991 and has since become the most prevalent mobile technology worldwide. GSMn, while not a distinct formal designation within the GSM standards, often implies a particular network operator's implementation or a specific software/hardware configuration related to GSM. These implementations can vary in terms of supported frequency bands, network features, and software versions.
The core functionality of GSM includes voice calls, SMS (Short Message Service), and data services like GPRS