01. 255 indoor phones for each door station at most;
02. Up to 8 door station for each building;
03. Anti-vandal and waterproof door station is optional;
04. Door station with IR LED to ensure clear picture even at night;
05. Digital door station or direct-call station is optional;
06. Keyboard with the night illumination to operate easily at night;
07. Talk and monitor with door station, unlock remotely and by password, each apartment has its own password;
08. Up to 2 indoor phones for each apartment;
09. Video and audio indoor phones are compatible;
10. Dingdong or chord music to be optional;
11. Indoor phone and the guard unit can call and communicate with each other;
12. Unlock by card to be optional;
13 Network or non-network system is optional.