Alarm indication signal: Difference between revisions

Revision as of 23:49, 27 June 2008

Revision as of 03:51, 2 July 2008

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* '''Alarm indication signal line''' (AIS-L)

Middle 20th century analog [[carrier system]]s had Carrier Group Alarms by which athe failure of a [[pilot signal]] was alerted to [[telephone exchange]] equipment, imposing an automated make-busy condition so the trunks carried by the failed system would not be used. The improved AIS originated with the [[T-carrier]] system, and became a standard feature of subsequent [[plesiochronous]] and [[synchronous]] circuit-based communication systems, and is also part of the [[asynchronous transfer mode|ATM]] standards.

As the use of [[Ethernet]] for long-distance data links has increased, the need for a similar end-to-end [[OA&M]] function has led to the development of a similar Ethernet alarm indication signal ([[EthAIS]]).