Once installedon the phone line, the SR learns the ring patternof each inbound call. It then automatically diverts the calls to the appropriate device or phone, without ringing other devices connected to it, surge protection and "Barge In" protection with busy signal, ensures privacy on the line. When the lineis in use by one device, other devices cannot "barge-in" and disrupt the call. SR-3 has a two-yearwarranty.