What is SONET?

SONET or Sychronous Optical Networking, is a new kind of technology that has helped to usher in the twenty-first century, where so much of business and life is based on digital communications. SONET and Synchronous Data Hierarchy (SDH) allow for better transmission of data signals over fiberoptic lines. This system uses lasers or LEDs, light emitting diodes, to send bits of data over cables. People who understand telecom engineering and look for the latest and greatest improvements, see SONET as a vital piece of a developing technology that will add speed to phone and internet communications while cutting costs over time.

The SONET system has replaced an older system known as a “PDH” system that facilitated many telephone calls over fiberoptic lines. Some experts call the PDH system a series of “metallic transmission systems.” A main problem with the previous system was the lack of standard operations in communication technologies.

After the breakup of centralized telephone communications in the U.S., the variety of regional companies had to combine efforts to maintain a grid for telecommunications. This was part of what led to the development of SONET. Also, those who are familiar with the history of these older systems have identified other problems with what existed before the new Sychronous Optical Networking system. Some say coaxial cable became costly to use in networks, and that many of the old lines were vendor-specific, which led to problems with the flexibility of the grids. Speed for transmission was also limited, according to experts, to 50 Mbps, something that the new system has far outdone.

The Sychronous Optical Networking system is based on clocks that synchronize signals and data sending. Technologies based on the SONET system have allowed for faster data transmission that supports some of the longer telecom supply lines now existing between regions of the world. An engineering idea called “multiplexing” has led to better and faster rates of data transmission, including the methods used for depth cables and international lines.

One fundamental idea involved in SONET is the use of multiple circuits to speed up and improve communications. The system also uses a combination of two methods called transport overhead and synchronous payload envelope or SPE to regulate rates of data transfer and to synchronize signals within the system. All of this has led to some surprising transmission capacities for today’s modern telecom installations.