4714 E1/T1 Local Alarm

Description

This alarm is reported when the E1 chip of the main control module does not receive correct signals and causes the interruption of the BTS transmission.

Attribute

Alarm ID Alarm Severity Alarm Type
4714 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.

64:DTMU/DOMU

87:GTMU
3 Board No.

Number of the fault board

0-7:DTMU/DOMU/GTMU
4 PassNo

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

Alarm sub-category number

0-23:E1 0-23 ports local alarm
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 services carried by the BTS are disrupted. The cells in coverage of the BTS are out of service. Call drops and handover failures occur.

System Actions

If the fault caused by the broken transmission link over the Abis interface is not cleared within 15 minutes, the BTS is reset.

Possible Causes

  • Incorrect settings of the DIP switch of the BTS
  • Transmission link failure over the Abis interface
  • Transmission link failure between the BTS and the BSC
  • Faulty TMU
  • Incorrect line coding configuration

Procedure

  1. For the BTS3006C/3002E, do as follows:
    1. Ensure that the DIP switch S1 of the DOMU is set properly, and then check whether the alarm is cleared.

      Digit 1 of the S1 set to ON: E1 transmission mode.

      Digit 1 of the S1 set to OFF: optical transmission mode.

      Y=> The alarm handling is completed.

      N=> Go to Step b..

    2. Ensure that the DIP switches S4, S5, and S2 are set properly, and then check whether the alarm is cleared.

      The S5 is used to set whether the rings of E1 line 1 and line 2 are grounded. ON: grounded; OFF: ungrounded.

      The S4 is used to set whether the rings of E1 line 3 and line 4 are grounded. ON: grounded; OFF: ungrounded.

      The S2 is used to set the impedance of E1 lines 1 to 4. ON: 75 ohm; OFF: 120 ohm.

      Y=> The alarm handling is complete.

      N=> Go to Step c..

    3. Check the transmission link of the BTS.

      Perform loopback on the RX0 and TX0 ports. Check whether the LIU0 of the DOMU is off when the SWT is off.

      Y=> Restore the transmission and check whether the alarm is cleared. The alarm is cleared. Alarm handling is completed. The alarm is not cleared. Go to Step d.

      N=> The fault may lie in the DOMU or the DLPU in the DMCM. Go to Step e..

    4. Check the peer transmission link.

      Perform loopback on the transmission line on the peer end. Check whether the LIU of the corresponding E1 line at the peer end is off.

      Y=> The transmission line at the peer end is functional. The fault may lie in the hardware. Please contact Huawei Customer Service Center.

      N=> The transmission line at the peer end is faulty. Rectify the fault, and the alarm handling is complete.

    5. Replace the DMCM and check whether the alarm is cleared.

      Y=> The alarm handling is completed.

      N=> Go to Step f.

    6. Replace the transmission lines between the E1_12 and E1_34 ports and the BSC or the upper-level BTS. Check whether the alarm is cleared.

      Y=> The alarm handling is completed.

      N=> The alarm is not cleared. Please contact Huawei Customer Service Center.

  2. For the BTS3012, do as follows:
    1. Ensure that the DIP switches S4, S5, S6, and S7 on the DTMU panel and SW6 and SW7 on the DCSU panel are set correctly. Then check whether the alarm is cleared.

      The S5 is used to set whether the rings of E1 line 1 and line 2 are grounded. ON: grounded; OFF: ungrounded.

      The S4 is used to set whether the rings of E1 line 3 and line 4 are grounded. ON: grounded; OFF: ungrounded.

      The S7 is used to set whether the rings of E1 line 5 and line 6 are grounded. ON: grounded; OFF: ungrounded.

      The S6 is used to set whether the rings of E1 line 7 and line 8 are grounded. ON: grounded; OFF: ungrounded.

      The SW6 is used to set the impedance of E1 lines 1 to 4. ON: 75 ohm; OFF: 120 ohm.

      The SW7 is used to set the impedance of E1 lines 5 to 8. ON: 75 ohm; OFF: 120 ohm.

      Y=> The alarm handling is complete.

      N=> Go to Step b..

    2. Check the transmission link of the near-end BTS

      Perform loopback on the RX0 and TX0 ports. Check whether the LIU1 of the DTMU is off when the SWT is off.

      Y=> Restore the transmission and check whether the alarm is cleared. The alarm is cleared. Alarm handling is completed. The alarm is not cleared. Go to Step c.

      N=> The fault may lie in faulty DTMU or destroyed DELC surge protection board. Or that the cable at the TRAN end is disconnected. Go to Step d..

    3. Check the peer transmission link

      Perform a loopback test on the transmission link at the upper level BSC or BTS. Check whether the indicator LIU corresponding to the peer E1 link is off.

      Y=> The peer transmission link is functional. The fault may be lie in hardware. Please contact Huawei Customer Service Center.

      N=> The peer transmission link is faulty. Repair the peer transmission link, and the alarm handling is complete.

    4. Replace the DTMU or DELC

      Replace the DTMU and DELC and check whether the alarm is cleared.

      Y=> The alarm handling is completed.

      N=> Go to Step e.

    5. Replace the cables

      Replace the cable between the TRAN port of the DCCU and the DCTB. Check if the alarm is cleared.

      Y=> The alarm handling is completed.

      N=> The alarm is not cleared. Please contact Huawei Customer Service Center.

  3. For the BTS3012AE, do as follows:
    1. Ensure that the DIP switches S4, S5, S6, and S7 on the DTMU panel and SW6 and SW7 on the DCSU panel are set correctly. Then check whether the alarm is cleared.

      The S5 is used to set whether the rings of E1 line 1 and line 2 are grounded. ON: grounded; OFF: ungrounded.

      The S4 is used to set whether the rings of E1 line 3 and line 4 are grounded. ON: grounded; OFF: ungrounded.

      The S7 is used to set whether the rings of E1 line 5 and line 6 are grounded. ON: grounded; OFF: DELU

      Replace the DTMU and DELU and check whether the alarm is cleared.

      Y=> The alarm is cleared. Alarm handling is completed.

      N=> The alarm is not cleared. Go to Step e.

    2. Replace the cables

      Replace the cable between the TRAN port of the DCCU and the DCTB. Check if the alarm is cleared.

      Y=> The alarm is cleared. Alarm handling is completed.

      N=> The alarm is not cleared. Please contact Huawei Customer Service Center.

  4. DBS3900/BTS3900:
    1. Check the DIP switches of the BTS.

      Check the settings of the DIP switches S1, S2, S3, S4, and S5 on the GTMU and correctly set the DIP switches according to their different functions, as described below:

      S1: Indicates the impedance of the first and second E1s. When bit 1 and bit 2 are set to ON, the 75-ohm E1 cable is used, when bit 1 is set to OFF and bit 2 is set to ON, the 120-ohm E1 cable is used.

      S2: Indicates whether the E1 cable is grounded. When all the bits of S2 are set to ON, the E1 cable is grounded; when all the bits of S2 are set to OFF, the E1 cable is not grounded.

      S4: Indicates whether the E1 transmission bypass is enabled. When all the bits of S4 are set to ON, the E1 transmission bypass is enabled; when all the bits of S4 are set to OFF, E1 transmission bypass is disabled.

      S5: Indicates whether the E1 transmission bypass is enabled. When all the bits of S4 are set to ON, the E1 transmission bypass is enabled; when all the bits of S4 are set to OFF, E1 transmission bypass is disabled.

      Then, check whether the alarm is cleared.

      Y => The alarm is cleared. No further action is required.

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

    2. Check the transmission link of the current-level BTS.

      On the DDF or the BTS side, perform the loopback operation for the RX0 and TX0 ports. Check whether the LIU0 LED on the GTMU is OFF when the SWT LED is OFF.

      Y => The LIU0 LED is OFF. Restore the transmission link. Check whether the alarm is cleared. If the alarm is cleared, the alarm handling is complete. If the alarm is not cleared, go to step g.

      N => The LIU0 LED is ON. The fault may be caused by the faulty GTMU or UELP.

    3. Replace the GTMU.

      Check whether the alarm is cleared.

      Y => The alarm is cleared. No further action is required.

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

    4. Replace the UELP.

      Replace the UELP to check whether the alarm is cleared.

      Y => The alarm is cleared. No further action is required.

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

    5. Replace the E1 cable.

      Replace the E1 cable of the UELP, then check whether the alarm is cleared.

      Y => The alarm is cleared. No further action is required.

      N => The alarm is not cleared. Contact Huawei Customer Service Center.

    6. Check the transmission link at the peer end.

      Perform the loopback on the transmission link from the BSC or the upper-level BTS. Check whether the LIU LED for the E1 link of the peer end is OFF.

      Y => The transmission link at the peer end is normal, and the fault may lie in the hardware. In this case, contact Huawei Customer Service Center.

      N => The transmission link at the peer end is faulty and needs repairing. After the fault on the transmission link is rectified, the alarm handling is complete.

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