This read-only on/off attribute, defaulting to off, indicates whether a Line-layer Remote Defect Indication is being detected by the OC-3 port. It tells an administrator that the far-end equipment is reporting back a defect it detected on the signal this port is transmitting. For example, an operator seeing this attribute turn on would know the problem lies with the outbound signal quality toward the remote end, prompting a check of the local transmitter or fiber connector.