2.0 Mb PRI Maintenance

Alarms

➤ Red: Near End Alarm (NEA)

When a Red alarm occurs, all B-channels are disabled. See PRI problems for possible solutions.
When the alarm is cleared, the PRI is automatically restored to service, and B-channels enabled.

Check the PRI Status and reset the counters in LD 60:

1. STAT loop - check PRI status
2. LCNT loop - list alarm counters
3. RCNT loop - reset alarm counters

➤ Yellow: Far End Alarm (FEA)

When a Yellow alarm occurs, all B-channels are disabled, and an alarm counter is incremented.
When the alarm is cleared, the PRI is automatically restored to service, and B-channels enabled.

BUT, if the 24-hour threshold (prompt RALM in LD 73) is reached, the PRI must be manually restored to service.

When the alarm is cleared, reset the counters and bounce (disable, then enable) the PRI in LD 60:

1. LCNT loop - list alarm counters
2. RCNT loop - reset alarm counters
3. DISL loop - disable loop
4. ENLL loop - enable loop

Counters

Counters are split into Group 1, Group 2, and 24 hour Group 2 total alarms. A healthy PRI will indicate all zeros (no alarm counts), otherwise a number indicates how often a particular error has occurred. When a threshold is exceeded, the circuit is out of service.

• LCNT (loop) List contents of alarm counters for loop (or all)
• RCNT (loop) Reset contents of alarm counters for loop (or all)

.lcnt 201

PRI2 LOOP  201
     MNT  NNDC   NNC   OOS
BPV- 000   000   000   000
FAP- 001   000   000   000
SLP- 000   000   000   000
CRC- 000   000   000   000
G2 - 000   000   000   000
                 MAINT      NONEWCALL  UNAVAIL    SEVERE
TOTAL 24HR BPV - 000000000  000000000  000000000  000000000
TOTAL 24HR CRC - 000000000  000000000  000000000  000000000
TOTAL 24HR FAP - 000000008  000000000  000000000  000000000
TOTAL 24HR SLPREP - 000000000
TOTAL 24HR SLPDEL - 000000000
TOTAL 24 HOUR G2 AIS  -000000000
TOTAL 24 HOUR G2 LFAS -000000000
TOTAL 24 HOUR G2 LMAS -000000000
TOTAL 24 HOUR G2 RAI  -000000000
TOTAL 24 HOUR G2 LOS  -000000000
TOTAL 24 HOUR G2 RAIE -000000000
.

Note: LD 60 as a background task, will periodically (~45 seconds) display and reset the alarm counters. Use during maintenance, when the circuit would otherwise be automatically disabled due to excessive slips. LD 17: CHG OVLY, BKGD 60 (LD 22: PRT OVLY).

Group 1 alarms are event-driven and include indicators that decrement a counter whenever an error is detected. Grade-of-service is changed based on how quickly the threshold of the counter is exceeded. The threshold count is determined in LD 73.

Group 2 alarms are either continuous or discontinuous. Grade-of-service is changed based on the duration of the alarm within a defined period of time. A minimum persistence time is defined in LD 73.

PRI Circuit problems

The PRI can have any of the following problems. Determine the cause of the problem and follow the recommended actions:

Symptom	Action
No connection to far end. (If you are not physically connected to the far end, frame-alignment errors occur. The channels will be disabled, the PRI will be in local-alarm mode.)	Check for wiring problems: Receive pair open Receive and transmit pairs open Corrupted data on receive pair
PRI fails self-test.	Replace the PRI card (not very common!).
Far-end problems, usually indicated by a remote alarm.	Check PRI status, and your local transmit pair integrity. Contact the far end to determine what action they are taking.
PRI is connected but getting bit-rate or frame errors. This can be caused by: bad or noisy cable connections electrical or electromagnetic interference carrier problems (for example, defective repeater)	Verify the wiring, and physical connection integrity. If the PRI in local alarm was a primary clock source, the software switches the clock controller to the secondary reference. Check the Clock Controller is enabled and locked.
Configuration settings do not match the far end. These problems can occur during initial start-up. They may be indicated by: DTA 018 - Frame-slip out-of-service limit DTA 021 - Loss-of-frame-alignment for 3 seconds DCH 1003 - D-channel DCH or MSDL errors	Confirm that the Meridian 1 PRI parameters correlate to the far-end parameters. Check the Clock Controller is enabled and locked. Confirm Alternate or CRC multiframe: E1 PRI Example.
Cannot enable the PRI. Two reasons follow: 1. The far end PRI is disabled, indicated by: PRI 000 - PRI is responding DTA 005 - Remote alarm occurred DCH 1010 - DCHI is software disabled 2. There is no 1.5 Mb/2Mb connection, indicated by: PRI 000 - PRI is responding DTA 021 - Loss of frame alignment for 3 seconds DCH 1010 - DCHI is software disabled	Verify the circuit is connected, and enabled at the far-end.
Meridian 1 initializes and there are no active B-channels.	When a PRI or ISL trunk interfaces with another Meridian PBX, you may have to disable and then re-enable each B-channel.

PRI Loop status:

PRI Channel status is found in LD 60 with: STAT loop.
- If loop is not entered, the status of all loops is output.

PRI2 LOOP x - STATE
SERVICE RESTORE: YES/NO                         ← restore automatically when alarm cleared
YEL ALM PROCESS: YES/NO                         ← yellow alarm processing enabled/disabled
ALARM STATUS: NO ALARM/RED(local) ALARM

Action 1:

1. list alarm counters (LCNT command)
2. check for DTA messages
3. see "PRI Circuit problems" (above)

Where: the card either did not respond to a status check, or did not respond when a red alarm was cleared. Go to Action 2.

Action 2:

1. check PRI loop status again
2. disable, then enable the PRI loop

When an alarm is present (group 2 error), it is a REMOTE ALARM.

PRI Channel status:

PRI Channel status is found in LD 60 with: STAT loop ch.

PRI Channel status:
IDLE	channel is enabled and idle
BUSY	channel is enabled and busy, or in a lockout state (far-end is disabled)
MBSY	channel is maintenance busy, the D-channel is down, or far-end channel is disabled
DSBL	channel is disabled
FE MBSY	near end is idle, far-end is maintenance busy
FE DSBL	near end is idle, far-end is disabled
FE DSBL	far-end B-channel is disabled
FE MBSY	far-end B-channel is in maintenance mode
UNEQ	channel is not equipped

D Channel status:

D Channel status is found in LD 96 with STAT DCH x.
- If x is not entered, the status of all D-channels is output.

The output format is:

DCH x : <Application_status> <Link_status> AUTO XX

Where:

For example:

>ld 96
DCH000
.stat dch
DCH 05 : DSBL  RST         AUTO  DES : E1_DID   ← this is down!
DCH 06 : OPER  EST   ACTV  AUTO  DES : E1_TIE   ← this is good!

NTAK79/NTBK50 Self-Test

A self-test is performed when the card is inserted, or manually invoked with SLFT L, or SLFT L CH (loop, channel), in LD 60.

• If the tests pass, the upper five LEDs blink simultaneously three times, and the card is returned to service.
• If the tests fail, the LEDs do not blink, the OOS LED illuminates, and a DTA105 L X message is output (where X is the failure code).

.disl 104                    you must disable the loop to run the self-test
.slft 104                    run the self-test procedure on card for loop 104

SLFT OK                      ← passed, or a DTA105 L X error is returned
.
XMI002 24  0 2  PRI2         ← after a self-test, the card is returned to service

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