It's actually an 8 volume History (I have all 8 on my shelf) 3 were just on switching system - you left out the parallel development to Panel, Rotary. Museum i

It's actually an 8 volume History (I have all 8 on my shelf) 3 were just on switching system - you left out the parallel development to Panel, Rotary. Museum in seattle also has a working 3ESS (likely the only one left in the world), and have recently added a DMS-10 as well.