Specifications

Chapter 6: Programming
Echo Thresholds
Page 6-142 Mitel
®
5000 Installation Manual – Issue 3.0, October 2008
Echo Thresholds
Specifications include several error thresholds. When an error exceeds one of these thresholds,
an error message is sent to the error message output port. If necessary, you can set the
thresholds for T1/E1/PRI errors in units of the number per hour and number per day. Thresholds
are set to default values that, in most cases, will not need to be changed. Possible errors
include the following:
• BPV (Bipolar Violations): This is a non-zero signal element that has the same polarity as
the previously received non-zero element.
• CRC-6 (Cyclic Redundancy Check): The calculation carried out on a set of transmitted
bits by the transmitter does not match the calculation performed by the system.
• OOF/COFA (Out of Frame/Change of Frame Adjustment): OOF is a state in which the
frame alignment that is received is not consistent with that which is transmitted. COFA
occurs when the system realigns its receiver to the proper frame alignment signal. This
could be caused by an incorrect line build-out (LBO) value.
• CS (Controlled Slips): The system replicated or deleted one 192-bit digital signal (DS1)
frame due to a lack of frequency synchronization. This could be caused by an incorrect
line build-out (LBO) value.
• ES (Errored Seconds): These are seconds in which at least one error occurred.
• SES (Severely Errored Seconds): This is a second during which transmission
performance is degraded below an acceptable level.
• UAS (Unavailable Seconds): This is the time interval during which the T1, T1/PRI, or E1/
PRI span is unavailable for service. This time begins with 10 or more consecutive
Severely Errored Seconds and ends with 10 or more Non-Severely Errored Seconds.
To program a threshold:
1. Double-click Error Thresholds to view the list.
2. To change a specific threshold, click the Value or Daily field, and then enter the new
number.
3. Press ENTER or click another field to save the change.