Intercoms can be both simple and complex, with many different kinds of set ups. All consist of a master station to sub-station setup, and how complex or simple they are depends on what kind of master station and sub-stations there are in the system.Sub-stations are any part of the system that relay information, voice, or video back to the master station.
than one location to receive calls from the sub-stations.
When a system is called “simple,” this means that communication can only go one way at a time. For example, the person at the master station will not be able to talk to the person at the sub-station, if the person at the sub-station is holding down their talk button, and vice versa. However, a complex or “duplex” system allows both parties to talk at the same time, if necessary. These systems do not require the user to push a “talk” button. How simple or complex a system is will usually affect its price. Simple systems will be less expensive than complex or duplex systems, but they do lack some of the more useful features.
Many intercom systems also come with the ability to be connected to electrified door locks, which means the intercom can actually lock or unlock a door, which is one great way to control access to a building, without having to have a security guard at every door.