1. Overview of keys

Pos.	Description	Feature
1	Mute Key	Toggles mute feature. Indicates phone and call statuses. See additional information in the table below (= Mute Key LED Indicators)
2	Touch Screen	Shows information about calls, soft keys, time, date, and other relevant data.
3	Volume(-) Touch Key	Lowers the volume of the speaker, ringer, or media.
4	Volume(+) Touch Key	Increases the volume of the speaker, ringer, or media.
5	Home Touch Key	Returns to the idle screen.
6	USB Type-C Port	Allows you to connect a USB flash drive (optional) to your phone so you can record calls/conferences and play back recorded files. Allows you to connect expansion PSTN box(es) (optional) to experience calls in PSTN. Up to two cascaded expansion PSTN boxes can be connected, so you can experience the local five-way conference conveniently in excellent speech quality with PSTN. Allows you to charge the Bluetooth Wireless Microphone CPW25.
7	Security Slot	Allows you to connect a universal security cable to your phone so you can lock down your phone. The phone will not be removed after locked.

Ref.	Key
Solid red	The phone is initializing. The phone is muted.
Flashing red	The phone is ringing.
Solid green	The phone is placing a call. There is an active call on the phone.
Off	The phone is powered off. The phone is idle.