Yeastar TG is a series of VoIP GSM/3G/4G gateway connecting GSM or 3G WCDMA or 4G LTE network toVoIP network directly and can support two-way communication: GSM/3G/4G to VoIP or VoIP to GSM/3G/4G.It is the best GSM trunking solution for IP-based telephone systems, the best fallback solution in case oflandlines outages, and also the best alternative for areas with limited landline or SIP connection.