Choosing the right intercom for your home
With so many different systems available and the inevitable march of technology it can be overwhelming trying to choose an intercom for your home.
In this article we break down the different components and decision points when choosing a system – from cabling to features, integration with existing or future systems or stand-alone.
One thing is certain, the doorbell of old has come a long way!
Intercoms come in 2 functional varieties: audio only and video. In general, if you want to open the door/gate remotely or see who is calling you would choose a video system. These can then become part of a CCTV solution essentially as an additional camera. If you just want to know someone is there and find out their business before letting them in you might choose an audio system.
Everything else is usually to do with how the systems connect, environmental conditions, additional functionality such as external relays, inputs, keypads, or RFID readers, and whether they integrate with other systems or stand-alone.
Intercom systems connect in one of 2 ways – physical connection (cable) or wireless. Within each of these are further variations such as:
Physical: multi-core cable, coaxial cable, optical fibre, 2-wire, cat5/6 (also multi-core).
Wireless: WiFi, 3G (mobile network), DECT phone system, 2-way radio, and using 3rd party radio equipment to provide connection such as point to point links.
Installing a physical connection is much more difficult and expensive in an existing home and is more cost effective during construction. Some established homes will have an old intercom system with multi-core cable which may be re-used with a new 2-wire system as long as the cable is in good condition. The choice is then to replace the old hardware with a later version from the same manufacturer or to utilise the cable to install a new system.
Distance between components will also affect the connection medium choice. WiFi and DECT will generally work ok with a door station at the front door (if video (WiFi), may need a booster) but will not work to a distant gate due to signal strength. There are ways to make this work but they require additional equipment and knowledge. In most cases a gate would use a physical connection due to distance but even then there are limitations which may require special long range ports on switches or optical fibre or even a point to point radio bridge. With distant door stations you may need to look at 2 way radio technology (EnGenius) or 3G systems that use the mobile network – or a point to point link. 2 way radio technology will not usually provide video and 3G will provide video but depends on the device receiving the call. These latter systems would typically be used on very large estates and would most likely be commercial installations rather than a home. They are there for home users if needed.
Analogue or Digital
Analogue systems carry voice and video on the connection media as wave froms representing the signal. Digital systems carry the voice and video as binary signals (sampled levels converted to binary numbers) representing the signal. The main difference is that digital will tend to have less noise especially over longer distances (please do your own research on the benefits of digital vs analogue) and voice and video can be easily carried over the same media. Digital typically will be carried as packets on an IP network allowing for easy integration with other devices and the internet.
IP further allows the use of protocols such as SIP for VoIP or Voice over IP as used in telephone networks. A SIP door station can call a telephone (mobile or fixed line) or any device with a SIP SoftPhone using technology currently used for modern communication. In a business or home environment the door phone becomes an extension on the local (or cloud) IP PBX providing great flexibility in call routing, forwarding, recording etc.
Non SIP IP systems may call dedicated devices and Apps on mobile devices via a push server and are less flexible in call routing.
An intercom system may form part of the access control system and therefore the security system in the home. The door station may provide several methods of access:
- Traditional call to the home owner who remotely provides access
- PIN Code through key pad on the door station
- RFID Card reader
- Finger print reader
- Call from a trusted device – mobile radio and 3G services will often register a phone as trusted thereby allowing access when called by the trusted device. Extra security may be offered by the caller entering a PIN code when prompted in the call.
All devices take power in the form of a direct power connection via Mains AC, DC (battery or plug pack), or as Power over Ethernet (POE). POE is carried over the same cable as the IP data simplifying installation of devices. POE is limited over long distance and there are devices specifically designed to allow for long distance POE and data. Where a device does not support POE you will need to establish a power connection to the device – local Mains GPO, low loss Low Voltage cable run, or renewable power source.
Integration with other systems
An intercom system may provide additional benefit if integrated with other systems. Examples of integration are:
- integration with a phone system. Some examples are:
- A DECT system where the door station is registered to a DECT base station and calls a defined handset or even a public phone number.
- A 2 way radio phone network such as the EnGenius SN902
- A SIP based system through a local or cloud IP PBX
- A Mobile network
- A standard PBX
- integration with a security and surveillance system. Functionality may include:
- integration with CCTV System for recording of intercom video or display of CCTV cameras on the intercom display panel. Video intercom systems typically allow for other camera views during a call to ensure visitors cannot hide before a door or gate is remotely unlocked
- integration with an alarm system – movement detection, tamper alarms, or security of the unlock system to ensure a door can only be unlocked if the security system is in the correct state.
- intercom terminal – this includes dedicated intercom terminal panels (video touch screens), multimedia telephones, mobile devices with appropriate App, and other devices as defined.
The choice of an intercom system for the home depends on many factors – function, connection, environment, power, and integration. Simply – what should it do, how should it do it, is there existing infrastructure we can re-use, where will it be, how do we power it, and what does it interact with. Simple!
If you would like some assistance is specifying a system for your home please contact us. We consider ourselves in the consulting and support business rather than sales. We provide ongoing support and are happy to discuss any issue long after the sale has been completed.