900 number

Premium-rate telephone numbers are telephone numbers for telephone calls during which certain services are provided, and for which prices higher than normal are charged. Unlike a normal call, part of the call charge is paid to the service provider, thus enabling businesses to be funded via the calls. While the billing is different, calls are usually routed the same way they are for a toll-free telephone number, being anywhere despite the area code used. These telephone numbers are usually allocated from a national telephone numbering plan in such a way that they are easily distinguished from other numbers. Telephone companies typically offer blocking services to allow telephone customers to prevent access to these number ranges from their telephones. In some jurisdictions, telephone companies are required by law to offer such blocking.

Adult chat lines (phone sex) and tech support are a very common use of premium-rate numbers. Other services include directory enquiries, weather forecasts, competitions and voting (especially relating to television shows). Diplomatic services, such as the US embassy in London or the UK Embassy in Washington, have also charged premium rates for calls from the general public.

In many European countries, for example France, Germany and the United Kingdom, it was common for organisations to operate customer service lines on premium-rate numbers using prefixes that fall outside the scope of the country's premium-rate number regulations. Therefore, in contrast to North America where customer service numbers are typically free of charge to the caller, consumers in Europe often used to pay a premium above the cost of a normal telephone call. The EU Consumer Rights Directive 2011/EU/83 came into force on 13 June 2014. It was supposed to eliminate this practice. Implementation detail, and hence the level of success in achieving this aim, varies considerably from country to country.

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Wikipedia