Thursday 15 November 2018

What is Rolling Code Technology?

Westlands Engineers Garador Electric Garage Door

When looking for an automated garage door fitted with an electric operator, you might be wondering about the different types of security integrated into modern electric operators and what security benefits they offer. You can view the full range of electric operator accessories currently available, on the Garador website. To understand why the technology for electric operators has been created, it is useful to understand how it developed… so let’s start by heading back to the 1960s.

Fixed Code radio signals (1960s – 1980s)

From the 1960s through to the early 1980s, fixed code radio signals were used with garage door hand transmitters and receivers. These were quite unsecure as the hand transmitter would always send the same fixed code and could easily be copied. Because the range of frequencies used to send fixed code radio signals was limited, you would sometimes get a ‘phantom garage door opening’, especially when neighbours used the same fixed code and their garages were in close proximity to one another.

Infrared Light Beam (1980s – 1990s)

During the 1980s and early 1990s, infrared light waves were used as a medium to open and close your garage door, but they also had major shortcomings. With bulky hand transmitters and large “box like” receivers installed on the outside of the garage, these devices had a limited transmission range and would not work from a long distance away. They also tended to be unreliable and because infrared is a form of light not a radio signal, if someone stood in the way of the space between the hand transmitter and receiver (effectively blocking the light beam), the garage door wouldn’t open or close. Furthermore, if there was bad weather such as mist, infrared based garage door openers wouldn’t work and if there was dust over the sensor on the infrared receiver, it wouldn’t work either.

Unsurprisingly, in the 1990s infrared was superseded by radio signal based hand transmitters and receivers, which used licensed 438 MHz radio frequencies, but this was short lived, as a new more widely used, unregulated signal frequency that didn’t require a license was to come to the fore…

433 MHz radio signals (2000s)

The 2000s witnessed the advent of 433 MHz radio signals. This technology has become far more prevalent than all of the other approaches over the last 30 - 40 years and its still used in many of the cheaper garage door hand transmitters and operator systems available on the market today. 433 MHz radio signals are unlicensed (meaning anyone can transmit using this frequency) and are therefore widely used in a variety of consumer products from car fobs through to baby monitors. So problems with signal interference and reliability when trying to open your garage door are still an issue, but not a critical one in many cases, as problems with signal interference, for example, are generally found in heavily built up areas with lots of devices in close proximity to one another (i.e. where a baby monitor used by a neighbour might interfere with someone’s garage door opener).

Over the past two decades we’ve seen the increased use of 433 MHz and 868 MHz radio frequencies to transmit signals. 868 MHz radio signals fall within the Ultra High Frequency (UHF) radio signal band that spans between 300 MHz and 3,000 MHz. Examples of equipment that use a UHF frequency are wireless LAN networks, television broadcasts and mobile phones, though they don’t necessarily use 868 MHz specifically.

Rolling Code Technology (2000s)

In the 2000s, the arrival of a new technology commonly known as “rolling code” or “hopping code” became more widely used in garage door operators and hand transmitters. You might have seen the term ‘rolling code’ technology when researching a new garage door with an electric operator, as it is generally supplied on operators sold here in the UK. The rolling code technology was originally developed for garage doors in the US and UK in response to people with homes and garages in the suburbs accidentally opening their neighbour’s garage, when the signal transmitted was the same. The great thing about rolling code technology is each time the door is opened or closed, a different frequency is used, and assuming the frequency being sent by the transmitter is the same as the one being expected by the receiver on the electric operator, the garage door will open. A hand transmitter using rolling code always sends out a different code from the one sent out previously.

Bi-directional Technology (2010s)

In the 2010s, bi-directional technology was developed; launched by Garador in 2011 it was a major leap forward in terms of security, reliability and range of signal transmitted by a hand transmitter to a receiver, in the form of an operator unit. Garador’s GaraMatic 10 and GaraMatic 20 operators both incorporate bi-directional technology, but the GaraMatic 9 does not.

The newly developed bi-directional technology uses 128-bit encryption; the same level of security that is used by high street banks to protect their customer’s details when doing online banking. The bi-directional radio technology also incorporated rolling-code technology, meaning that a different frequency code is sent each time the hand transmitter was used to open the door and this means that it is incredibly difficult to copy.

The bi-directional operators and hand transmitters use a licensed 868 MHz radio frequency; the term “licensed” means the frequency is reserved for Garador hand transmitter signals only and hence it is very unlikely you will experience signal interference from a baby monitor, for example, as was sometimes the case with 433 MHz radio signals.

The 868MHz radio signals also have a longer signal range, so you can operate the garage door from further away. This is especially notable when compared to hand transmitters with 433 MHz radio signals which had a shorter range. The use of bi-directional radio technology means it is almost impossible to copy the signal.

To find out more about Garador’s hand transmitters and operators, check out the Garador website at