Loud background noise in group calls.

In eLTE network ,sometimes we will face the background noise is loud in group calls.

the possible causes are as below:

1. The volume of the vehicle-mounted terminal is too high.

2. The interconnection cable is in poor quality.

so we need check:

1. Decrease the volume of the vehicle-mounted terminal and then check the group call quality.

2. Replace the interconnection cable and then check the group call quality.