If the apartment intercom stops responding to calls from the Outdoor station (see image 1), it is likely that the settings on your apartment intercom have been reset. To get the intercom back online, simply follow these steps. If the screen buttons are not responding to presses, please have a look at this solution How To Re-calibrate the Screen before proceeding with this solution.
Image 1- Outdoor station
If you are not able to receive calls from the Outdoor station on your apartment intercom, you will show a disconnect 
From the home screen (press the 
Image 2 - The home screen
On the settings screen, press and hold the Project Settings Icon (see image 3 in Red). If a password box appears, enter password 888888 and then press OK to continue.
Image 3 - Settings Screen
After selecting the Project Settings icon, youll be presented with the Project Settings screen (see image 4)
Image 4 - Project Settings Screen
Check the value next ro Room No (see Image 4 in Red). Make sure this aligns with the room number you are in. If not, change it to the correct value and then press the OK button (see image 4 in Red). You should get an message to suggest this has updated and if all goes well, the network icon 
Once you have confirmed the settings on this screen, press the Network icon on the right side menu (see image 5 in Red)
Image 5 - Network Settings
Connecting the Front Door
Check VTO IP Address and make sure it is set to 192.168.1.110. If it isnt, press in this area and enter it in. Press the OK button (see image 5 in Orange) to save. If this is completed correctly, the red cross in the
Connecting the underground Carpark
Press the right arrow (see image 5 in Green). This will bring up the underground carpark VTO details. As per the instructions in "Connecting the Front Door", make sure the VTO IP Address is set to 192.168.1.199 and if not, set this and press OK.
Note: If you are still having trouble with your intercom after going over these instructions, please direct all support requests to your body corporate.