S50 is a compact and full-featured IP-PBX that comes in a 19’’ 1U rack-mountable chassis. The advanced module-based S50 is capable of supporting ISDN BRI, PSTN, and GSM connectivity, providing VoIP communications for up to 50 users.
With Yeastar S-Series, all the telephony interfaces are modular and customizable, S20 support 2 onboard module slots to custom FXS, FXO, ISDN BRI, GSM/3G/4G.