Zhone Technologies IMACS-200 - Manual (Page 141)

WAN Ports 5-11
WAN ports WAN port User Screens and Settings
DM
A Degraded Minute (DM) is any minute during the reporting period that has an error rate
greater than 10-
6
as described in ITU-T G.821. The count for this field is from 1 to 15, rather
than 1 to 900 for the other fields.
STATUS
If one of the described errors occurs during any of the 15-minute intervals, the status column
for that period would display the code for that error. The codes are displayed at the bottom of
the screen. The values are Y (Yellow Alarm received), N (No Signal), T (Test Mode - line
loopback, local loopback, payload loopback, or standby), L (Loss of Synchronization – 2 out
of 4 frame bits in error), B (Bipolar Violation), and E (Excessive Error Rate).