❤ Adopt two-way voice intercom communication technology, which can automatically recognize and process voice signals without any operation during the call. Professional anti-sidetone processing chip with automatic mute function can effectively improve voice. ❤ Application of automatic call control. The integrated design of the microphone of the external machine and the speaker can be directly connected to the host, and the installation is convenient and simple. ❤ Internal and external two-way voice signal output (recorded by the bank accountant) and stereo jack output mode, which can prevent the power switch and function buttons from controlling the voice recording function. It has anti-interference and noise-free functions. Also supports two-way audio recording output. ❤ The auxiliary machine can be hung on the wall or glued to the glass by double-sided adhesive. The dual-channel adjustment with channel dynamic indicator is more convenient to use. ❤ Internal volume knob and external sound knob can adjust internal and external volume respectively. The *N indicator above the controller indicates the host's speech during intercom, and OUT indicates the slave's speech