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17 • T1/E1 Link
T1/E1 DACS Administrators' Reference Guide
Line Status (dsx1LineStatus)
This variable indicates interface line status. It contains loopback, failure, received alarm and transmitted alarm
No Alarms
Alarms Present
information. If any condition other than
exists, you can click on the
link to view
Line Status Alarms
the
window (see figure 43).
Figure 43. Line Status Alarms window
The alarms currently present on the line will be indicated by the
ACTIVE
label next to the alarm type.
Failure States
The following failure states are reported in the dsx1LineStatus object. The items listed in this section comprise
those contained in RFC 1406—Definitions of Managed Objects for the DS1 and E1 Interface Types.
Far End Alarm Failure
Far End Alarm failure is also known as a Yellow Alarm in the T1 case or Distant Alarm in the E1 case.
For D4 links, the Far End Alarm failure occurs when bit 6 of all channels has been zero for at least 335 ms. The
alarm is cleared when bit 6 of at least one channel is non-zero for a period T, where T is usually less than 1 sec-
ond and always less than 5 seconds. The Far End Alarm failure is not declared for D4 links when a Loss of Sig-
nal is detected.
For ESF links, the Far End Alarm failure is declared if the Yellow Alarm signal pattern occurs in at least 7 out of
10 contiguous 16-bit pattern intervals. The alarm is cleared when the Yellow Alarm signal pattern has not
occurred for 10 contiguous 16-bit signal pattern intervals.
For E1 links, the Far End Alarm failure is declared when bit 3 of time-slot zero is received set to 1 on two con-
secutive occasions. The Far End Alarm failure is cleared when bit 3 of time-slot zero is received set to zero.
120
Line Status (dsx1LineStatus)
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