These procedures work on both Single Line sets and Multi-line sets. Lift handset and listen for dial tone. The eight participants can be any combination of inside and outside parties. The expanded conference feature is always available as a special extension number of the system, except when locked by an active conference. You can think of this number as an open room ready to be entered unless it has been closed by someone already using it.
Any station can establish an expanded conference call.
It is basically no more than dialing an extension. However, a conference leader must coordinate the conference for two reasons. The leader must set the time and notify the parties. The leader can also control the access to the conference so that uninvited parties cannot listen in. Entry to the conference is unobtrusive and parties will not know someone has entered unless they speak.