Yeastar S50 Central, a unique and distinctive design for small, large and medium companies, supports 50 users (50 internal lines), supports 25 simultaneous calls, contains 8 FXS/ FXO/ BRI ports, supports 4 GSM/ 3G/ 4G mobile lines. Features of Yeastar S50 Central Call Transfer Database CRM Call Recording Conference Calls IVR Tree Real-time Reports and Analytics Yeastar S50 Central Specifications Designed specifically for small, large and medium companies. Supports 50 users (50 extension lines). 25 simultaneous calls, has 8 FXS/ FXO/ BRI ports. Supports 4 GSM/ 3G/ 4G mobile lines.