What does stm-1 mean in optical fiber network transmission?

STM-1, or Synchronous Transport Module level 1, is a standard used in optical fiber networks for transmitting data. It supports a data rate of 155.52 Mbps and is a fundamental building block in the Synchronous Digital Hierarchy (SDH) used for high-speed data transport. STM-1 is designed to carry various types of data, including voice, video, and data services, and allows for the multiplexing of lower-rate signals into a single higher-rate stream, facilitating efficient and reliable communication over optical networks.