Greeting the caller, reporting that all the operators are busy at the moment, plays music during waiting in queue, requests to stay on the line as the next available operator will pick up exactly your call.
This function available in some telephone networks allows redirecting the incoming call to another telephone, for example, a mobile phone, a box of voicemail or another telephone number where the called subscriber is situated. In such a way the subscribers can, for instance, receive calls that have arrived at their work number from their home or mobile phone.