Yeastar D30 extension expansion module

• Yeastar D30 DSP module increases extra 100 extensions & 30 concurrent calls capacity on select yeastar models including Yeatar S100, S300, P560, P570
• It is used to expand the capacity of S-Series PBX.
• For each Yeastar D30 module added, the max amount of users increase by 100 while concurrent calls increase by 30.