The music industry is out of tune with consumers, according to campaigners for digital technology.

The Campaign for Digital Rights (CDR) is protesting at record companies allegedly adding copyright-protection systems to CDs.

Jason Kitcat, Brighton co-ordinator for the CDR, said: "The restrictions prevent discs from working on all platforms.

"Until now, a music CD will work when put in a standard player, a computer CD drive or emerging multi-purpose devices, such as PlayStation 2.

"But, without any discussion, this has changed. CDs are being manufactured in such a way that they can only be played-back on standard CD players."

The group has been distributing leaflets outside major music stores to raise public awareness.

It has identified several different limitation methods, which it says are being introduced on CDs.

Mr Kitcat said: "Different record companies are using different ways to protect their CDs. A least one or two of the systems work by creating intentional errors on the disk.

"On a normal CD player, these errors do not make much difference because the machine is designed to accept a few flaws and read around them.

"It's not the same for computers. They will believe a disc with errors is corrupt and it will not operate at all."

The British Phonographic Industry represents the interests of more than 200 British record companies, which account for 90 per cent of recorded music output in the UK.

A spokeswoman said: "As far as we know, there are not any commercially available copy-protected CDs in the UK. But it is really important to allow artists to protect their work in this digital age.

"CD burning (copying of data to CD) is taking place at an unprecendented scale. Global music sales fell by five per cent for the first half of this year and there's a real concern CD burning is a contributing factor."

Mr Kitcat said: "I always buy the real product but then I want to copy it for my other platforms. When I buy a CD, I do not expect to have to buy it four times over to have one copy in my home, another in my car, another for my computer and yet another for my mini-disc player."

The CDR is compiling a database of titles limited by copyright protection and wants to hear from anyone who has found a CD which does not play successfully on their equipment. The group hopes to determine the copy-protection schemes in use and the impact for the purchaser.

Information can be emailed to dodgy-cd@uk.eurorights.org uk.eurorights.org/issues /cd/