Installed ACS 7.0 and 5 18D phones. Customer has 3 lines. On extensions 14, 17 & 18 you can be using line 1 while in conversation with a caller. During that time if a call comes in on line 2 it creates a disrupting static ring cadence into the ear piece while your talking. What I mean by static ring cadence is that during the transmission of incoming ring there is choppy static that overrides the current sound transmission. It acts like defective call waiting.

Anyone ever experience this scenario?