YeaStar NeoGate YST-TG200 QuadBand 2 Port VoIP Gateway connect GSM or WCDMA or 4G LTE to VoIP networks to provide two-way communication: GSM/3G/4G to VoIP and VoIP to GSM/3G/4G. This allows you to connect most IP-based telephone systems including Yeastar IP Phone Systems,