The other consideration is what capabilities do you need. Do you want to see who is at the door? If so then a video intercom is needed. A camera will go at the front door and will communicate with one or more monitors on the inside. There is even a wired system that enables you to use a smartphone or tablet PC to see who is at the door.
Almost all systems have the ability to unlock the door from inside as long as you connect two wires from the intercom over to an electric door strike or maglock. The lock is not included with the intercom so you will have to provide that. A locksmith would be able to install the proper lock type for your door type.
If you would like assistance in choosing a system for your needs, please call 1-888-298-9489.
To see the systems available, click here: door intercom
