What Does Synchronous Transport Module Level-1 (STM-1) Mean?
Synchronous Transport Module level-1 (STM-1) is a fiber optic network standard for synchronous digital hierarchy. The transmission format is considered the fundamental building block for synchronous digital hierarchies. Apart from the fact that higher rate signals are created by multiplexing numerous STM-1 signals, lower rate payloads are also mapped into STM-1.
Techopedia Explains Synchronous Transport Module Level-1 (STM-1)
The Synchronous Transport Module level-1 frame structure has nine rows and 270 columns of bytes, totaling 2,430 bytes. It is a byte-oriented arrangement with a bit rate of 155.52 Mb/s. The frame is transmitted at 125 µs, resulting in 8,000 frames per second on the circuit. The frame of STM-1 consists of payload blocks, overhead blocks and pointers. The ratio of these components largely depends on the initial payload that needs to be transmitted. While the last 261 columns of the frame provide the information payload, the first nine available columns contain the overhead and administrative pointers. The administrative pointers can contain one or more virtual containers which have the path overhead or the virtual container payload information.
