Editing Crossbar switch (section)

===Instrumentation===
For instrumentation use, [[James Cunningham, Son and Company]]<ref>{{cite book |title=The Pursuit of Excellence |first=Noël |last=Hinrichs |publisher=James Cunningham, Son & Co |date=1964 |chapter=6. The Era of Automation |chapter-url=http://www.obs-us.com/people/karen/cunningham/chapter6.htm#47 }}</ref> made high-speed, very-long-life crossbar switches<ref>{{harvnb|Hinrichs|1964|loc=[http://www.obs-us.com/people/karen/cunningham/47.htm Crossbar Switch]}}</ref> with physically small mechanical parts which permitted faster operation than telephone-type crossbar switches. Many of their switches had the mechanical Boolean AND function of telephony crossbar switches, but other models had individual relays (one coil per crosspoint) in matrix arrays, connecting the relay contacts to [x] and [y] buses. These latter types were equivalent to separate relays; there was no logical AND function built in. Cunningham crossbar switches had precious-metal contacts capable of handling millivolt signals.