You may not know but niche product that is hot-selling on Amazon - doorbell. By considering the market size of Amazon, something selling well on Amazon could be safely assumed having a big demand in market.

We are in the physical security industry, how could we exclude this highly related product from our regular product list? Let's explore this market segment together.

There are different setups for a doorbell (or intercomm) system. May I suggest we could start with one type that is low-cost but very powerful and could be easily accepted by general household.

Doorbells and intercom systems are essential for receiving guests and callers without making them wait. Audio or video, wired or wireless, there's a range to suit all tastes in both new-build and home renovation - from simple bells to high-tech videophones.

The doorbell, a slight technical advance on a bell placed above a doorway, is the most basic means of signalling your presence. You press the button and <brrrring!> the doorbell goes off. While it's fine for letting you know that someone's at the door, it doesn't let you speak to or identify the person. It just rings and rings.

Intercom systems, by adding audio transmission, let you chat to whoever's outside. They can trigger remote door opening if the door is equipped with an electric door release. This can be very useful if you have a large garden or when the weather is bad and you don't want to go out in it. The most advanced models, which incorporate a camera - hence the name videophone - also let you see the person calling at your door. Even more secure!

Wired or wireless?

Wireless technology is highly convenient because it lets you install your doorbell or intercom without having to pass wires from outside to inside your home. Some systems even let you take the doorbell chime, the handset or the intercom monitor with you. Great if you want to avoid putting a separate chime in every room of the house! However, wireless systems are less reliable because of the potential for interference and are also limited in range. The ranges specified by manufacturers apply to an open, unobstructed space. Overspec your system's range to take into account intervening walls or other obstacles that might limit the signal. Also be careful to keep an eye on battery wear!

How does a wired doorbell work?

A wired doorbell consists of a button placed by the outside door, connected to a chime that you place inside your home. Choose a central location so as to remain in earshot wherever you are in the house.

Your choice of button should take into account resistance to wear and bad weather as well as your personal taste. The chimes often have several ringing tones and a volume control. They can run on high-voltage mains power if the doorbell is inside (i.e. apartment blocks), but should be low-voltage (e.g. 12V) if installed outdoors, to avoid electrical accidents.

The chime should allow volume and ringing tone to be adjusted.

Since it's a wired device, a power supply is necessary - with all this may involve (connections, passage of 2.5mm² wires, potential losses, etc.).

What are the key boxes to tick with an intercom?

A recessed mounting plate is less of a target for vandals than a protruding model, although this can be fixed on a greater variety of surfaces. Also check that the plate offers sufficient weather protection.

A backlight is very handy for nighttime use, especially if your intercom is located in an area away from streetlights etc.

For its strength and durability, aluminium combined with zamak is a great choice!

What is IP weather protection system?

The IP code ("IP" followed by two digits) can be found on all electrical and electronic devices intended for outdoor use. The figures appearing after the "IP" represent the level of protection against weather. Here's how to interpret the two digits:

First digit:

0, no protection;
1, protection against solid objects greater than 50mm;
2, protection against solid objects greater than 12.5mm;
3, protection against solid objects greater than 2.5mm;
4, protection against solid objects greater than 1mm;
5, some dust protection;
6, protection against all types of dust.

Second digit:

0, no protection;
1, condensation protection;
2, protection against light rain up to 15° from the vertical;
3, rain protection up to 60° from vertical;
4, protection against splashing water from any direction;
5, protection against jets of water;
6, protection against any kind of soaking including e.g. sea waves;
7, protection against brief immersion;
8, protection against permanent immersion.

Just combine the two tables to work out your device's protection level!

How to choose your videophone?

A videophone is an intercom with a camera at the entry point and a corresponding screen at the handset end. Images can be captured in colour or black and white, depending on the model. Make sure the outdoor panel has a light or night mode to let you see any night owls as they arrive. Also take into consideration the screen size at the handset end. The bigger the screen, the better chance you have of identifying your visitors! On the other hand, the handset device will take up more space. Some videophones can be set to take a picture of any visitors if you're not there, a bit like an answering machine!

As for image quality, you'll have the choice of either digital or analog. Digital offers superior picture quality, while analog may suffer from interference resulting in a blurred image.

Camera angle is also an important factor; the wider it is, the more you see on your monitor screen.

High-end models of videophone can be connected with smartphones.

One last tip to stay connected?

If you're renovating, go for a wireless system; choose wired for new-build.

In a flat, or if you have a small garden, a doorbell should be sufficient. If you have a large garden, you're paranoid about missing the postman, or you live in a bit of a "likely" area, choose an intercom or even a videophone that will provide maximum security and comfort when coupled with an electric release or automated gate. Without going as far as barricading the door, it's always good to avoid unwanted visitors!