4102 TRX LAPD Link Interrupt Alarm

Description

The Carrier Module reports this alarm upon detecting that an LAPD link is not available.

Attribute

Alarm ID Alarm Severity Alarm Type
4102 Major Fault

Parameters

ID Name Meaning
1 Site No.

Number of the site where the faulty board or module is located

Value range: 0-2047
2 Board Type

Number of the type which the faulty board belongs to.

65:DTRU/GTRU/DDRM

88:DRRU

92:DRFU

96:MRRU

100:MRFU

101:GRFU

102:GRRU

151:QTRU
3 Board No.

Number of the fault board
4 PassNo

Number of the passage where the faulty board is located.
5 SubLink No.

Alarm sub-category number

255:None
6 Cell Index

Index of the cell where the board or module is located

0-2047: Cell index of the faulty cell in the data configuration

65535: None
7 Site Type

Type of the site where the faulty board is located.

12:BTS3012;

13:BTS3006C;

14:BTS3002E;

15:BTS3012AE;

16:BTS3012 II;

17:DBS3900 GSM;

18:BTS3900 GSM;

19:BTS3900A GSM;
8 RackNo

Number of the rack where the faulty board is located.
9 BoxNo

Number of the subrack where the faulty board is located.
10 SlotNo

Number of the slot where the faulty board is located.
11 Site Name

Site Name
12 Alarm Attribute

Alarm Character

0:Normal

1:Transient Count

Impact on the System

The TRX cannot communicate with the BSC. Therefore, the faulty TRX cannot carry services normally and automatically shuts down the power amplifier. If the faulty TRX is the BCCH TRX, the services of the cell where the faulty TRX is located are disrupted.

System Actions

When the LAPD alarm is generated, the TRX tries to reset the interface chip. If this alarm is generated on the BCCH TRX and if the TRX aiding function is enabled, the BCCH switchover is triggered in the case that this alarm is not cleared within two minutes.

Possible Causes

  • Incorrect settings of the DIP switch of the BTS
  • Incorrect data configuration
  • Transmission failure between the BSC and the BTS
  • Main control board failure
  • BSC Abis interface board failure

Procedure

  1. Check the TRX board where the alarm exists according to the alarm information.
    1. exists on all the TRXs in the TRX board.

      Y => The alarm exists on all the TRXs in the TRX board. Go to step b.

      N => The alarm does not exist on all the TRXs in the TRX board. Go to 2.

    2. Reset the TRX. Check whether the alarm is cleared.

      Y => The alarm is cleared. The alarm handling is complete.

      N => The alarm is not cleared. Go to 2.

  2. Check for other related alarms according to the alarm information.
    1. Check whether 4714 E1/T1 Local Alarm or 4716 E1/T1 Remote Alarm is reported on the LMT.

      Y => 4714 E1/T1 Local Alarm or 4716 E1/T1 Remote Alarm is reported on the LMT. Go to step b.

      N => Neither 4714 E1/T1 Local Alarm nor 4716 E1/T1 Remote Alarm is reported on the LMT. Go to 3.

    2. Rectify the fault according to handling suggestions in 4714 E1/T1 Local Alarm or 4716 E1/T1 Remote Alarm. Check whether the alarm is cleared.

      Y => The alarm is cleared. The alarm handling is complete.

      N => The alarm is not cleared. Go to 3.

  3. Check the BTS application scenarios.

    In the case of combined cabinets or cabinet groups, go to step a. In the case of cascaded BTSs, go to step k.

    In other cases, go to [4].

    1. Based on the alarm information, determine whether the alarm is located in the extension cabinet, extension cabinet group, or lower-level BTS.

      Y => If the alarm is located in the extension cabinet or extension cabinet group, go to step b. If the alarm is located in the lower-level BTS, go to step j.

      N => The alarm is only located in the main cabinet. Go to 4.

    2. Check the primary and secondary links of the main cabinet group and extension cabinet group and the transmission link between the main cabinet group and extension cabinet group.
    3. Check the connection between the CC_OUT port on the DCSU and the DCTB in the main cabinet.
    4. Check the cable connections for combined cabinets.
    5. Check the connection between the CC_IN port on the DCSU and the DCTB in the extension cabinet.
    6. Check the connection between the TO_DTRB port on the DCSU and the DTRB in the extension cabinet.
    7. Check for bent or broken pins of the connectors of the backplane or boards that are involved in step b through step e.
    8. Replace the faulty components involved in step b through step e. Check whether the alarm is cleared.

      Y => The alarm is cleared. The alarm handling is complete.

      N => The alarm is not cleared. Go to step i.

    9. Check whether the TRX in the extension cabinet or extension cabinet group is faulty.

      Y => A faulty TRX exists. Go to step j.

      N => No faulty TRX. Go to 4.

    10. Replace the TRX in the extension cabinet or extension cabinet group. Check whether the alarm is cleared.

      Y => The alarm is cleared. The alarm handling is complete.

      N => The alarm is not cleared. Go to 4.

    11. Check the transmission between the current-level BTS and the upper-level BTS. Contact the maintenance engineers to rectify the transmission fault. Meanwhile, check the TRXs of the current-level BTS. Replace the TRX that is faulty. In the case of combined cabinets or cabinet groups, perform step b through step k.
    12. Check whether the alarm is cleared.

      Y => The alarm is cleared. The alarm handling is complete.

      N => The alarm is not cleared. Go to 4.

      NOTE:

      Combined cabinets or cabinet groups are not applied to the BTS3036/BTS3900 series.

  4. Check the transmission link of the current-level BTS.
    1. Check the transmission link of the current-level BTS.

      Y => The transmission link of the current-level BTS is normal. Go to 5.

      N => The transmission link of the current-level BTS is abnormal. Go to step b.

    2. Contact the maintenance engineers to rectify the transmission fault. Then, check whether the alarm is cleared.

      Y => The alarm is cleared. The alarm handling is complete.

      N => The alarm is not cleared. Go to 5.

  5. Check whether the 64 kbit/s timeslot cross-connection or timeslot compressing devices are used.

    Y => The 64 kbit/s timeslot cross-connection or timeslot compressing devices are used. Go to 6.

    N => The 64 kbit/s timeslot cross-connection or timeslot compressing devices are not used. Go to 8.

  6. Check whether the data on the timeslot cross-connection device is consistent with the on-site data.

    Y => Consistent. Go to 8.

    N => Inconsistent. Go to 7.

  7. Reconfigure the timeslot cross-connection device. Check whether the alarm is cleared.

    Y => The alarm is cleared. The alarm handling is complete.

    N => The alarm is not cleared. Go to 8.

  8. Check the TRX.
    1. Log in to the LMT to check the TRXs for faults.

      Y => A faulty TRX exists. Go to step b.

      N => All the TRXs are normal. Go to 9.

    2. Reset the TRX. Check whether the alarm is cleared.

      Y => The alarm is cleared. The alarm handling is complete.

      N => The alarm is not cleared. Go to step c.

    3. Replace the TRX that is faulty. Check whether the alarm is cleared.

      Y => The alarm is cleared. The alarm handling is complete.

      N => The alarm is not cleared. Go to 9.

  9. Check the DIP switch of the BTS.

    Check the settings of the DIP switch bits on the TMU. Ensure that the settings are correct. Check whether the alarm is cleared.

    Y => The alarm is cleared. The alarm handling is complete.

    N => The alarm is not cleared. Go to 10.

  10. Replace the TMU. Check whether the alarm is cleared.

    Y => The alarm is cleared. The alarm handling is complete.

    N => The alarm is not cleared. Go to 11.

  11. At the Abis interface board of the BSC corresponding to the BTS with the alarm, check whether all the other BTSs have the same alarm.

    Y => All the other BTSs have the same alarm. Go to step a.

    N => Not all the other BTSs have the same alarm. Go to step b.

    a Replace the BSC Abis interface board. Check whether the alarm is cleared.

    Y => The alarm is cleared. The alarm handling is complete.

    N => The alarm is not cleared. Go to step b.

    1. Contact Huawei Customer Service Center.

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