IS-136 is a digital mobile communication standard developed for the second generation (2G) of cellular networks. It was primarily used in North America and is also known as TDMA (Time Division Multiple Access). This technology allows multiple users to share the same frequency channel by dividing the signal into time slots, improving the efficiency of the network. The IS-136 standard supports voice and data services, enabling users to make calls and send text messages. It was widely adopted in the 1990s but has since been largely replaced by more advanced technologies like 3G and 4G, which offer higher data speeds and better overall performance.