If the
Enable Transfer on ‘Hook on‘" option is enabled in SwyxIt!, both call partners are connected with each other if you hang up your receiver. If more than one call is on hold, however, your call partners are not connected when you hang up. Instead, all calls are placed on hold and a warning sound is played after 5 seconds. By picking up your receiver, you are directly connected to the last active call.
See also
10.2.1 General.