4718 AIS Alarm

Description

The alarm is triggered when the BTS transmission is interrupted because the upper level BTS has not received correct E1 signals.

Attribute

Alarm ID	Alarm Severity	Alarm Type
4718	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?15:abnormal transmissions with the upper level BSC or BTS over E1 ports 00?0F
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 BTS cannot communicate with the peer device through the E1/T1 port where the alarm occurs. If the peer device is the BSC, some or total services of the current-level BTS are disrupted.

System Actions

If the BTS services are totally disrupted, the BTS tries to perform the link setup. If the link setup cannot be complete in 15 minutes, the BTS is automatically reset.

Possible Causes

Broken link
Incorrect settings of the DIP switch of the BTS
Faulty boards

Procedure

Check whether a link disconnection exists in the Abis-interface transmission network.
1. 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 LIU LED is off. Go to 2.
  
  N => The LIU LED is on. Go to step b.
2. Contact the transmission engineers to rectify the transmission faults. 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.
Check the DIP switch of the BTS.
Check the settings of the DIP switch bits SW6 and SW7 on the DCSU, and the DIP switch bits S4 through S7 on the DTMU. Ensure that the settings are correct. Check whether the alarm is cleared. The descriptions of DIP switch bits are as follows:

SW6: For selecting the matched impedance from the first to the fourth E1 ports. Note that ON indicates 75 ohm and that OFF indicates 120 ohm.

SW7: For selecting the matched impedance from the fifth to the eighth E1 ports. Note that ON indicates 75 ohm and that OFF indicates 120 ohm.

S5: For selecting the grounding of jackets for the first and second E1 links. Note that ON indicates that the E1 link is grounded and that OFF indicates that the E1 link is not grounded.

S4: For selecting the grounding of jackets for the third and fourth E1 links. Note that ON indicates that the E1 link is grounded and that OFF indicates that the E1 link is not grounded.

S7: For selecting the grounding of jackets for the fifth and sixth E1 links. Note that ON indicates that the E1 link is grounded and that OFF indicates that the E1 link is not grounded.

S6: For selecting the grounding of jackets for the seventh and eighth E1 links. Note that ON indicates that the E1 link is grounded and that OFF indicates that the E1 link is not grounded.

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

N => The alarm is not cleared. Go to 3.
Replace the main controlling module. 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.
Replace the BSC interface board. Check whether the alarm is cleared.
Y => The alarm is cleared. The alarm handling is complete.

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