If you have an AA-07FB, there is a good chance that your department already has an intercom set up. When someone dials your intercom, they should hear both the answer tone (2 beeps) and the initiator voice. The function key should light up with the incoming call banner.
If this does not happen, you may need to check the settings. To do this, open the PoE Switch Manager app on your phone and select "Settings" on the top menu bar. Under "Settings," select "Intercom Settings" and make sure that "Handsfree Only" is selected. If you still have trouble hearing people when they call, try turning off all sound settings on your phone - this will allow you to hear everyone on the line, even if your sound is muted by another user in a group chat. If none of this helps, go to https://bas-ip.com/features/.

Thank you for your help. I could not have figured this out without you. Still, I feel that I should have gone straight to Basip and gotten some advice from him. Perhaps then I would not have suffered so much trying to solve the problem. And so, I had to change this technique.