Additional Details ------------------------------ Product description: Model: YST-EX08 Yeastar IP PBX Expansion Board EX08 Yeastar EX08 is an expansion board with eight external RJ-11 ports and four internal card slots for adding compatible Yeastar modules. The EX08 fits into a Yeastar S100 or S300 IP-PBX to give custom functionality to your VoIP phone system. Available modules offer: 2 FXS, 2 FXO, 1 FXS/1 FXO, BRI, GSM and 3G. Yeastar S300 Expansion Board for Yeastar S100 and S300 systems Supports up to 4 optional modules/8 ports, including O2, S2, B2, GSM, UMTS, and CDMA modules Add up to 2 expansion cards to S100 and 3 to the S300 Product Image: