Abstract: A conference arrangement is disclosed having a plurality of logical multiport bridges for conferencing customer stations. Equipment units common to the bridges can be selectively connected to a station controlling each bridge. Upon the detection of a faulty unit, the interaction between the controlling station and the bridge is halted while a new unit is substituted. Announcements prompt the controlling station to reactivate the transaction that was halted. If the controlling station is off the bridge when the fault is detected and substituted equipment is unavailable, the station is forced back on the bridge, until a new unit becomes available.