The Yeastar TG200L is a 2-Port 4G/LTE VoIP Gateway that directly connects mobile networks with IP-based telephone systems, enabling bidirectional communication between LTE/4G and VoIP networks. As a fallback solution in case of a landline failure, it provides a cost-effective and reliable backup to maintain telephone connectivity in businesses. Integration into existing IPPBX systems or softswitch solutions is simple and quick, thanks to high compatibility and a web-based management interface. SMS messages can be sent and received via a web interface, including support for mass SMS. By utilizing mobile-to-mobile calls and SIP trunks, significant cost savings on telephone expenses can be achieved. The device supports various voice codecs such as G.711, G.722, G.729A, and Speex, as well as DTMF modes like RFC2833 and SIP Info. Echo cancellation is performed according to ITU-T G.168, ensuring clear voice quality. NAT traversal functions such as Static NAT and STUN ensure stable network connections, even in complex environments. The gateway features two 10/100 Mbps Ethernet ports and supports network protocols including FTP, TFTP, HTTP, SSH, QoS, VLAN, and OpenVPN. Operating temperature ranges from 0°C to 40°C, while storage temperature ranges from -20°C to 65°C. Power supply is provided via DC 12V/1A or AC 100–240V. Dimensions are 213 x 160 x 44 mm. The devices are designed for indoor use and are ideal for businesses requiring redundant communication infrastructure.