The Yeastar TG400 GSM Gateway is a professional VoIP-to-GSM gateway designed to connect GSM networks with IP-based telephony systems. Featuring 4 GSM channels, the TG400 enables businesses to make and receive calls between GSM and VoIP networks, helping to reduce communication costs and improve call routing flexibility. It supports the SIP protocol for seamless integration with IP PBXs such as Yeastar, Grandstream, Panasonic, Asterisk, 3CX, and other SIP-compatible systems. With advanced features including SMS support, least cost routing, call forwarding, caller ID management, and a user-friendly web-based interface, the TG400 is an ideal communication solution for businesses, call centres, hotels, and enterprise environments.