Customer called and said Ext. 21 used to ring by itself for 1 ring cycle on incoming calls, and if not answered after first ring, all other phones on system would ring, so she would never miss a call if away from her desk. After most recent hydro outage, does not ring in this order anymore. Can someone tell me how I could re-program this feature, please. Rings at Ext.21 first and if not answered after first ring, all other phones will ring ..