With Rückruf statt Warten (Callback instead of waiting), callers do not have to stay on hold in a call queue. They leave a callback request and hang up. The phone system calls back automatically as soon as someone on the team becomes free.
The function only applies to call queues, not to ring groups or individual extensions. For busy extensions, there is Callback on busy.
Who sees what: The view is reserved for the administration. Others see „Nur für Administratoren“ (Administrators only) with „Die Rückruf-Einstellungen sind Administratoren vorbehalten.“ (The callback settings are reserved for administrators.)
Prerequisite: there is at least one call queue, see Ring groups and call queues. Otherwise it shows „Keine Warteschlangen“ (No call queues) with the notice that the callback only applies to call queues.