The remotes of the roller door motors we fit (Herculift and Long Lift) use rolling-code technology. This article explains the idea simply, what the numbers mean, and how to keep your remote secure.

The idea

Each press sends a different code, and the motor never accepts the same code twice. Even if someone captures the signal, they cannot replay it to open your door.

Picture a long list of codes that never repeat, which the remote and the motor both know the order of. Each press uses up a new code, and someone who records the code just used gains nothing, because it is already spent.

How it works inside

In systems of this kind the remote and the motor's receiver share a mathematical algorithm and a secret value. On each press the remote calculates the next code and sends it with a counter, and the receiver checks and accepts it. Systems generally allow a small window of upcoming codes, because the remote may be pressed out of range and get ahead of the motor. Once a code is accepted, earlier ones are never accepted again.

The numbers

  • Remote frequency: 433.92 MHz.
  • Possible combinations: over 4.29 billion.
  • Motor force: 380 N at 220 V.

That many combinations means guessing a code at random is not practical. The frequency is simply the radio channel the remote uses to talk to the motor, and it is common for remote controls.

Programming and adding remotes

Usually each remote is paired with the motor by a programming step the technician performs: the receiver is put into learning mode and the remote is pressed. The same process lets the technician clear the stored remotes and register only the ones you want. If several people use the door, ask for the number of remotes you need from the start, and note who holds each.

How to keep your remote secure

  • Do not leave the remote in a car parked on the street, as it may go with the car.
  • If you lose a remote, ask the technician to clear the stored remotes and re-register only those you want.
  • Order a spare remote through the installer rather than copying one from an unknown source.
  • Replace the battery when response weakens or range shortens. It is the first thing to check.
  • Keep remotes away from children, since random presses can move the door while they stand close.
  • Avoid leaving the remote in a hot car in summer, or exposing it to water.

If the motor stops

The motor can be released by cable so the door can be opened by hand. When the power is back or the fault is fixed, put the motor back into drive mode.

Common mistakes

  • Assuming a rolling-code remote means you no longer need to care about actually closing the door.
  • Leaving the remote on a key ring handed over at car washes or service bays.
  • Neglecting the battery, then assuming the motor has failed.
  • Pressing the button repeatedly while the door is moving. Wait until it stops.
  • Pressing the remote many times far from the door, which can put it out of step with the motor.

Common questions

Can the signal be captured and copied? A signal may be captured, but the motor does not accept the same code twice, so replaying it does not work.

What is the remote frequency? 433.92 MHz.

What should I do if I lose the remote? Contact whoever installed the door so they can cancel it and programme a new one.

Why does the remote only work close to the door? Usually a weak battery, metal obstruction or interference. Changing the battery is the first step.

Summary

  • Rolling code sends a new code on every press, and the motor will not accept the same code twice.
  • Over 4.29 billion combinations at 433.92 MHz.
  • Look after your remote, cancel lost ones, and remember the cable release is there in a fault.

Full details on the automatic roller doors page. For gates: sliding and swing gates.