STM-4

The STM-4 (Synchronous Transport Module) is a SDH ITU-T fiber optic network transmission standard. It has a bit rate of 622.080 Mbit/s.

The STM-4 specification is designed to carry 7,680 8-bit "voice" frames every 125 micro-seconds for a total payload bit rate of 491.520 Mbit/s. The other levels defined by the SDH standard are STM-1, STM-16, STM-64 and STM-256. Beyond this we have wavelength-division multiplexing (WDM) commonly used in submarine cabling.

Although STM-4 is comparable to OC-12 the SDH frame structure allocates more space to overhead than that of SONET. Because of this, STM-4's payload bandwidth differs from that of OC-12.

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.