This OID counts, in bits, how many line-coding violations have been detected on the inbound signal of this WAN 10G SONET (WAN-PHY) interface. A coding violation is a fundamental transmission-layer error detected in the signal's line code itself, so this counter is one of the earliest indicators of a degrading optical or electrical signal on the receive side, before it necessarily shows up as an errored second. For example, a slow rise in coding violations on a 10G WAN-PHY interface carrying SONET-framed Ethernet across a long-haul span while the interface otherwise stays up could indicate an aging optical transceiver approaching end of life.