How Wired Intercoms for Automatic Gates work
Intercoms for automatic gates generally have an Outdoor Station at the gate with a Call Button that when pressed rings an Indoor Station like a door bell except an occupant may answer the call and speak to the visitor to identify them before letting them in. They do so by pressing a button on the Indoor Station that will either open an automatic gate or release an electric pedestrian gate or entry door lock.
The advantage of a wired intercom if used with a pedestrian gate or entry door is you don't need any power at the gate/door as power is provided by the same wiring as the intercom. If the intercom is used with an automatic gate, unless its solar powered, the gate motor will require power anyway so wiring for the intercom may as well be installed at the same time, although the source of power and the inside station are normally in different locations so wireless intercoms can have an advantage here too particularly with multi story buildings where running cables inside can be difficult.
The disadvantage of a wired intercom as opposed to a wireless intercom is installing the wiring, which can cost many times more than the purchase price of the intercom although this isn't always the case. You may think OK installing a wired intercom is a more durable and permanent solution than a wireless intercom but you can spend a lot installing a wire and find it isn't heavy enough for the job or after a while you forget its there and get some work done in your yard and someone cuts through it by mistake and you can't just join intercom wiring in the ground as joins in the ground will fail sooner or later so the entire cable would need to be replaced. You also need to use intercom wire that is suitable for going in the ground otherwise this too will fail sooner or later.
Handsets work much like a land line phone when a visitor calls and the occupant picks up the handset to answer and can speak to the visitor like they are on the phone accept the outside station works like a speaker phone. A handset also has one or more buttons to open one or more gates.
Some Intercoms are Hands free so when called the occupant just pushes a button and talks like they're using a speaker phone. Mounted on a wall hands free intercoms are very handy if the occupant has their hands full and can't pick up a handset. Also handy if more than one person is to communicate with a visitor before letting them in. Another advantage of hands free is it cannot be "left off the hook" by mistake leaving it out of action as a hands free intercom automatically turns itself off if not being used ready for the next call.
Video Intercoms are the same as audio intercoms but have a camera in the Outdoor Station and a small colour flat screen monitor on the Inside Station so an occupant may also see who's at the gate before letting them know they are home. The video only goes one way so the visitor can't see the occupant. They also have a small Infra red light on the Outdoor Station to see a few metres in the dark.
If you wish members of your family, friends, tradesman or the meter reader to have access you can add a digital keypad next to your intercom so anyone with a correct pin number can open the gate weather someone is home or not. A digital keypad is either a separate stand alone device that can be added or some intercoms have them built in to release a lock or open an automatic driveway gate. A second keypad or weather proof press button may be added inside the gate to allow people to get out too.
Extra Inside Stations
Some intercoms have the option of more than one inside station, which work the same as a single but the occupant has a choice of locations they can answer a call from. These intercoms quite often have a call button to call all other internal stations allowing communication between rooms. The internal call button has a different ring tone than the outside station so occupants know if its the gate or an internal call. Some intercoms have more than one call buttons to allow individual rooms to be called.
Extra Outdoor Stations
If there are two or more pedestrian gates, automatic driveway gates, doors or a mix of either some Intercoms have more than one outdoor station that calls inside with a different tone so the occupant knows which gate is calling. Some handsets even know which gate is called so opens only that gate with a single button keeping things simple.
Calling More than one House or Office
If there are two or more Residence or Offices sharing one or two gates there are Intercoms that have two or more call buttons or if there are more than 16 it is more practical to have a Digital Keypad for entering a Residence or Office number.
Digital Modular Systems
If there is a number of different gates and more and/or users then a Digital Modular System allows any combination of Outdoor and Indoor Stations to be used. Modular Outdoor Stations allow the installer to select what they would like to have on a single Outdoor panel. They can choose between Audio and Video, Individual Call Buttons or Digital Call buttons that also doubles as a Digital Keypad for Access Control.
Using the Telephone Network.
For established Gated Communities, Apartment or Office buildings an Intercom that is connected to the standard telephone network and has a digital keypad that allows visitors to call many different house hold or office phones or mobile phones to speak to the occupant who can then open the gate using the keypad on their phone. The visitor dials only the house, apartment or office number or uses alpha numeric search to find the occupants name if they don't know their number and the Intercom calls the number programmed into it for that occupant.
The Advantage of this system is the only cabling required is that to the nearest point where a connection can be made to the land line telephone network eliminating the need to run cables to every house, apartment or office saving a lot of money and avoiding the mess created digging up existing landscaping to install cables. Also the digital keypad can be used to gain access without making a call so long as a visitor has a valid pin number.
The disadvantage is you need a dedicated phone account for the Intercom, which costs per month plus any call costs. Less people have land line phones these days favouring mobiles and call costs to mobile phone can add up if there is a lot of them.
For Apartment buildings and Office Blocks there is quite often access to the telephone lines running into each apartment or office, if this is the case then these lines can be interrupted to make a connection eliminating the need to connect to the telephone network, which means there would be no call cost but will not work with mobile phones.