The volume control of the Becker device must be set to the AIR Control Display so that it can also control the full volume range of the radio. Without this setting, the volume is not fully selectable and most of the time the radios are too quiet or too loud.
The following must be done in the ACD-57 menu:
- Enter PIN code 3000
- MENU > COM SYSTEM > INSTALLATION > SPK VOL SRC
- This item should be set to "PRI CH
- With this setting, you determine that the ACD has full control over the volume.