A redundantly constructed protection channel access transmission apparatus includes current units and spare units by which protection channel access data can be transmitted even if any one of the current units or spare units is in an alarm state. In a normal state, the current units transmit work data...http://www.google.fr/patents/US5506833?utm_source=gb-gplus-shareBrevet US5506833 - PCA transmission apparatus and PCA transmission method
PCA transmission apparatus and PCA transmission method
