An ATM exchange system which handles fixed-length cells, such as an ATM exchange, is designed in such a manner that even when a failure occurs particularly in an interface unit or an ATM switch section, downstream stations can be informed of the failure reliably and that when some failure is detected,...http://www.google.com.au/patents/US6246665?utm_source=gb-gplus-sharePatent US6246665 - Method for attending occurrence of failure in an exchange system that exchanges cells having fixed-length, and interface unit and concentrator equipped in the exchange system using the method
