Nortel Networks 1000 User Manual

Page 232

232

NT5D11 and NT5D14 Lineside T1 Interface cards

Lineside T1 card enters line processing mode and a yellow alarm
message is sent to the CPE/CSU. Line processing sends the Meridian
1 either all "on-hook" or all "off-hook" signals depending on the dip
switch setting of the card.

When the Set Alarm command is used, a prompt appears to set the
threshold level and duration period for alarm levels 1 and 2.

The threshold value indicates the number of bit errors detected per second
that is necessary to activate the alarm. The T1 link processes at a rate of
approximately 1.5 mb/s. The threshold value can be set between 3 and 9
and can be different for each alarm level. Any other value entered causes
the software to display a "Parameter Invalid" message. The threshold
number entered represents the respective power of 10 as shown in

Table

93 "T1 bit error rate threshold settings" (page 232)

Note:

The error rate threshold for a level 2 alarm must be greater (a

smaller power of 10) than for a level 1 alarm.

Table 93
T1 bit error rate threshold settings

Alarm Threshold

bit errors per second

in Power of 10

Threshold

to set alarm

Allowable

Duration Periods

–3

1,500/second

1–21 seconds

–4

150/second

1–218 seconds

–5

15/second

1–2148 seconds

–6

1.5/second

1–3600 seconds

–7

1.5/10 seconds

10–3600 seconds

–8

1.5/100 seconds

100–3600 seconds

–9

1.5/1000 seconds

1000–3600 seconds

The duration value is set in seconds and can be set from 1 to 3600
seconds (1 hour). This duration value indicates how long the alarm lasts.
Low bit error rates (10-7 through 10-9) are restricted to longer durations
since it takes more than one second to detect an alarm condition above
10-6. Higher bit error rates are restricted to shorter durations because the
MMI error counter fills at 65,000 errors.

If the Set Clearing (S C) "Enable Self Clearing" option is set, the alarm
indications (LEDs and external alarm contacts) clear automatically after the
duration period expires. Otherwise, the alarm continues until the command
set Clear Alarm (C A) is entered.

Nortel Communication Server 1000

Circuit Card Reference

NN43001-311

02.06

Standard

27 August 2008