Keeping the front door of an apartment building or office unlocked  is at best risky. 

Keeping the door locked is the only real option.  A door intercom to the residents from the front door is therefore essential.

A video entry systems intercom will provide the residents with the considerable benefit of being able to see their visitor as well as speaking to them on the phone.  A number of systems offer many and varied features:

• Multiple video intercom handsets to allow calls to be answered any where in the house.
• Variety of panel finishes – stainless steel, brass, etc
• Moving cameras beside the Intercom panel
• New flat panel intercom stations.