Save your TimeThis office phone support receiver/headset/hands-free answering methods, which can maximize work efficiency and save your time ^^ Noise Cancellation MicrophoneProvide superior high quality sound and shield 95% background noise so as to perfectly and truly voice since equipped with noise canceling microphone ^^ FSK/DTMF Caller ID Display The dialer can ring or silent when receive incoming calls as well the phone number will be displayed. It can store 62 groups of incoming calls, 16 outgoing groups ^^ Adjustable VolumeThe Ringer and Headset volume can be adjusted up to 40 dB. You can hear the other party's voice clearly even in a noisy environment.
(Note: the Speakerphone and Handset Volume does not support adjustment ) ^^ Easy to UseSimply connects call center telephone to existing standard telephone jack. Adjust the sound with the volume button, insure high quality sound and flexible listening experience.
Note: It powered by the phone line. So, it still works when power outage