Patton electronic Model 2604 Line Status dsx1LineStatus, Failure States, Far End Alarm Failure

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 information. If any condition other than No Alarms exists, you can click on the Alarms Present link to view the Line Status Alarms 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)