In DK280 how remove Talk option in display phones

Do you mean that you want to MUTE the speaker microphone?

Hi;
Thanks for your response.
This is my situation; If I receive a phone call, and for some reason I'm busy to answer that phone call, in the other side the user can use one option in the phone display called Talk(pressing the Page botton), they can used as a interphone, and they can start talking
I want to disable that option.

There is no option in programming to not allow voice calling to your PDN. You can place your phone in DND or fixed forward to vmail if you don't want to take calls. If you're proficient with the system programming or have a tech do it, you can place a PhDN on your phone and make it your prime extension number. When someone calls your extension number it will ring on your PhDN button but they caller cannot switch to voice announce.