Your question about PolycomSoundStation2W expandable

Technical Specifications

• Ideal for small and medium conference rooms seating up to 10 participants
• Dynamic Noise Reduction (DNR) actively removes background noise such as projectors and ventilation systems
• 360-degree microphone coverage with intelligent mixing highlights  
• No more buzz technology resists interference from mobile phones and other wireless devices
• Wireless protocol: 1.8 GHz DECT (1.880–1.900 GHz); 1.9 GHz DECT 6.0 (1.920–1.930 GHz); 2.4 GHz WDCT (2.401–2.483 GHz)
• Rechargeable lithium-Ion battery pack
• Connections for two additional microphones (not included in the scope of delivery) 

Compatibility

• The Base Station connects to any standard analog telephone line
• The SoundStation2W can also function as a Wireless GAP-User in existing systems

Scope of Delivery

• SoundStation2W
• Power Supply EU for SoundStation2W
• Base Station Analogue
• Power Supply EU for Base Station
• Battery