Comment: Interference threatens broadband

Just over a year ago, the European Commission asked three European standardisation bodies - CEN, Cenelec and Etsi - to create a set of standards to regulate the radio emissions from fixed telecoms networks, including Digital Subscriber Line (DSL) broadband services.

This was a response to reports of interference to radio services caused by wired communications systems. The EC was particularly concerned about interference to public safety and emergency services.

While laudable in theory, any proposed regulation will be far from straightforward. Complications exist in the form of similar laws in several European countries: in the UK we have MPT1570 and in Germany there is NB30. Etsi and Cenelec have formed a joint group to review these standards and tweak them for Europe-wide application. If only it were that simple.

First, there is the argument about whether these should be conformance or enforcement standards. Conformance standards are used to test that systems meet the requirements and a compliance certificate is usually issued.

Enforcement standards only come into play if someone complains. The regulatory authority then investigates and, if there is an infringement, forces the source of the interference to stop or takes some other remedial action. In the UK, that authority is the Radiocommunications Agency.

Second, various parties say the current standards are not stringent enough to protect radio services. They propose new restrictions, and their reasoning is plausible.

Tightest restrictions

Among these parties is a group, led by the BBC, which proposes the tightest restrictions of all. The BBC limits on radio interference are about 1,000 times stricter than those of MPT1570. This has caused some consternation among telecoms operators and equipment manufacturers because the BBC limits would probably make many DSL systems unworkable, especially if they run on overhead distribution cables.

The BBC says that as DSL systems become more widespread, interference to medium-wave radio will get worse and, in many cases, the affected radios will be very close to the telephone wires carrying DSL.

This proximity issue is very important. My portable radio works fine in the kitchen, for example, but if I take it into the study where my computers are, it just emits an awful buzzing sound. This interference with the radio signal is all caused by emissions from the computers, printers and other electronic devices in the vicinity. Admittedly, I don't have ADSL, but that's another story...

The upshot of all this is that the Etsi/Cenelec group has been unable to reach agreement on what to do, and has decided to ask the national standards bodies, such as the British Standards Institute (BSI), for their views on the proposals.

This may not prove a good idea, however, because the BSI is not a totally open organisation and it may be difficult for interested parties to make their views known. I hope that the BSI will announce some sort of public consultation process; this is such an important issue that it must be made easy to express an opinion and influence the UK view.

Radio listeners and users of broadband services alike should watch this process closely.

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