With the Busy-on-Busy function, calls to a group can be limited in such a way that they can be meaningfully handled by the logged-in group members. If the Busy-on-Busy limitation takes effect, the group is no longer accessible. Other callers will then hear the busy tone. Call forwardings and multi-path call forwardings are still possible.

If the announcement before answering is enabled at the same time, the Busy-on-Busy function can be used to limit the number of calls put on hold in the waiting loop. This prevents more callers from being connected to the waiting loop than can be answered in the available time. Waiting callers are held for a maximum of 8 minutes.

If the announcement before answering is disabled, Busy-on-Busy should be switched on dynamically depending on the available group members.