Local control unit CZ1522.
Features:

• Volume control
• Power on, power off
• Function change button (combined with STIF)
• Ability to drive from up to 10 active speakers 
• Priority for emergency microphone messages with volume by-pass and power switch

In addition:

Blue power LED
1 input for audio signals with maximum 12Vpp
1 stereo output (also configurable as L+R) for active speakers type 508, 530

Power supply: 24 Vdc
Dimensions: 35 x 35 x 50 mm

NOTES: the module is compatible with electrical mounting boxes and cover plates, it can be installed on rectangular or round or square boxes, using one of the specific command adapters.