What is Repetitive Electrical Impulse Noise (REIN)?

REIN is a common reason behind slow broadband speeds and disconnections. It's often referred to as interference and is caused when electrical noise from an external source interferes with the internet signal. The interference can be caused by electrical equipment that causes additional noise in the same band of radio frequencies as your broadband service.

What type of equipment causes REIN?

Common causes of REIN are:

• Ignition systems in central heating boilers
• Christmas lights (especially flashing ones)
• Thermostats
• Motors
• Pumps
• Fans
• Faulty power adaptors
• Railway power lines
• Street lights
• Roadworks

Faults in equipment like set top boxes, televisions, and other appliances can also be the cause of interference, along with poor internal wiring.

Christmas tree lights (especially the type that flash) are another common cause of interference.

Any item of electrical equipment can cause REIN. In most cases, the interference will be within your own home, but it is possible that neighbours' equipment could also be causing the interference, or there could be a source along the route the telephone line takes from the KCOM exchange to your home.

How can I work out what's causing the interference?

The best starting point is to make sure your broadband is connected through the master socket (also known as the NTE). For help with this, please see 'How do I test my broadband or phone in the NTE test socket?'.

If your interference has started recently, and your broadband drops or slows down when a new electrical item is on, the next thing to do is test if it is the cause. Turn it off, then turn your router off. Wait a few seconds before turning your router back on. If your broadband starts to run as normal again, then your electrical item is the cause of the interference. Try moving the item away from the telephone wiring, and make sure they're not plugged into the same power supply or extension socket as the router.

You can use the same process of elimination for all items of electrical equipment. Try to look for a pattern for example, if your broadband slows or disconnects when your central heating is switched on, switch the boiler off then turn your router off and on again after a few seconds.

If you can't locate any single appliance that's causing the interference, turn off all the electrical equipment in your home and switch each item back on one at a time, monitoring your broadband performance until you find the problem appliance.

REIN caused by equipment that's not in your home

If none of the electrical equipment in your home appears to be causing the interference, you'll need to look further afield. It is possible that equipment in a neighbour's home is the problem. Talking to neighbours about their broadband service may help you locate the cause of the interference.

If the problem is a source along the route the telephone line from the exchange to your home, other people will be experiencing similar issues. If they are, noting down the times and days broadband issues occur will help locate the interference source.

What to do if you can't locate the source of interference.

If you've followed the steps above and you're confident that the course of the interference isn't in your home, and you haven't been able to locate and stop it by talking to your neighbours, then you can report it to KCOM by calling Technical Support on 01482 606101. Opening hours are Monday - Friday, 7am to 10pm, Saturday 7am-6pm, and Sunday 8am-6pm. We would also recommend that any of your neighbours affected by interference phone and report it too.

Investigating the source of interference outside of customers' properties can be complicated, and may take us several months. In some cases, if we find the source of interference and it's outside of our control, we may not be able to eliminate it.