Nortel NT1R20 Description page 196

Page 172 of 290
553-3001-105 Standard 5.00 June 1999
NT5D33 and NTRB34 Line-side E1 Interface Cards
When you select the Set Alarm command, you will be prompted to set
the threshold level and duration for alarm levels 1 and 2.
The E1 link processes at a rate of approximately 2.0 mb/s. The threshold
value indicates the ratio of the total number of bits that must be detected as
being in error per second before the LEI activates an alarm. It can be set
between 3 and 9 and can be different for each alarm level. Any other value
entered will cause the MMI to display a "Parameter Invalid"
message. The digit entered as the threshold value is a number representing a
negative power of 10 as shown in Table 45.
Note: The error-rate threshold for a level 2 alarm must be greater (a
smaller power of 10) than for a level 1 alarm. Remember that the
numbers being represented are negative numbers. Since 3 represents -3,
and 4 represents -4, 4 represents a smaller number than 3 does.
Table 45
E1 bit error rate threshold settings
Alarm threshold bit
errors per second in
power of 10
-3
10
-4
10
-5
10
-6
10
-7
10
-8
10
-9
10
The duration value is set in seconds and can be set from 1 to 3,600 seconds (1
hour). This duration value indicates how long the alarm condition must last
before an alarm will be declared. Low bit-error rates (10
restricted to longer durations since it takes more than one second to detect an
alarm condition above10
durations because the MMI error counter fills at 65,000 errors.
Threshold to set
alarm
2,000/ second
200/second
20/second
2.0/second
2.0/10 seconds
2.0/100 seconds
2.0/1000 seconds
6
. Higher bit-error rates are restricted to shorter
Allowable Duration
Periods
1-21 seconds
1-218 seconds
1-2148 seconds
1-3600 seconds
10-3600 seconds
100-3600 seconds
1000-3600 seconds
7 9
through 10 ) are