GSM: A Phone Network for the Whole World

GSM stands for Global System for Mobile Communications. The GSM Cellular network is one of the early leaders and longtime champions of cell phone networks. It has been around (MORE)

Point-to-Point Internet Communication

Session Initiation Protocol (SIP) determines a lot about what your communications network can and can't do. An important part of learning this technology is understanding your (MORE)
In Devices

Premium Cellular Phones and Services

Increasing demand for functionality has led to a huge increase in the development of special phones. Not all of these devices conform to usual standards for what constitutes a (MORE)