This read-write value sets the network-side monitored-events count for this frame relay port, such that if N392 errors occur within N393 events on the network side, the interface is marked down. Paired with casfFrLmiNetN392, it's the network-side monitoring window that determines exactly how many of the last N393 signaling exchanges have to show errors before this switch, acting as the network side, marks the interface down for the customer. NetN392 of 2 with NetN393 of 5 means the switch tolerates two bad exchanges out of any five before declaring the customer-facing frame-relay service down.