Noises occur in a call, the call is disconnected, or other unknown faults occur when the AT0 trunk of the SoftCo is used.
Step 1 Check the AT0 ground.
For details, see AT0 Ground Check(Note:Download).
Step 2 Test the ground impedance.
For details, see AT0 Ground Impedance Test(Note:Download).
Step 3 If the fault persists, contact Huawei technical support engineers.
The possible cause is that the AT0 ground is poor.