Yeastar YST-U200 MyPBX Hybrid IP-PBX VOIP Telephone Routers for Business. Modular Technology - Customizable combination of FXO, FXS, BRI,GSM, and UMTS modules. No future licensing fees - Scalable with plug-and play ease without licensing. Redundancy - Support hot standby settings (automatic failover) in case of server failure. Energy Saving - Low power consumption for your green office. Match your IP phone - Perfect interoperability with major IP Phones.