Callback
Callback is a special method that can be used in telephony, whereby return calls can be requested from a service provider. The actual connection is established by a service provider that does the calling back. This makes it possible to conduct calls via a different telephone provider from the one that provides your telephone line or mobile telephone, and be billed by the third party service provider. This method is often used to optimise phone charges or to give employees the opportunity to make calls via their own work phone connection, without the company incurring the costs of private telephone calls. It can also be used when a company's phone line does not support Call-by-Call, to allow them to select another phone service provider to make calls through.