※ high-grade aluminum 2U black drawing panel, nice; ※ able to adapt with a variety of different types of switches connected to use; ※ call automatically connected, after the call automatically hang up; ※ Call ringing times optional with built-in four-ring number of times to select the switch; ※ built-in high-fidelity 5W / 8Ω full-frequency monitor speakers; ※ monitor and output volume independently adjustable; ※ has a short circuit activation signal input port; ※ with a manual answer and hang up function;
