Yeastar S100 IP PBX is a cost-effective business communication system with a base configuration of 100 users and 30 concurrent calls and can scale up to 200 users and 60 concurrent calls. Yeastar MyPBX S100 built with responsiveness, accessibility and productivity. S100 work most effectively as a office telephone system.The flexible S100 comes with support for analog ports, ISDN BRI, E1/T1/PRI, and GSM networks.With Yeastar S100, you have invested in a solution that evolves with your company at the same time lower the cost of  initial investment.