This counts frames this interface transmitted during the current RMON history collection interval that were flagged with a CRC error; notably an outbound CRC error is unusual because a healthy transmitter shouldn't generate its own bad checksums, so a nonzero count here often points to a hardware fault in the transmit path itself, a failing framer chip, for instance, rather than a receive-side or cabling issue. Troubleshooting typically assumes CRC errors are a receive-side symptom of bad cabling, so seeing them counted on egress specifically should redirect the investigation toward the local interface's transmit hardware. A NOC engineer seeing this counter climbing on one specific interface, while inbound CRC counters elsewhere stay clean, would prioritize swapping that interface's transceiver or line card over chasing a cabling problem.