TELECOM Digest Editor noted in response to Scott Dorsey:
[TELECOM Digest Editor's Note: I know that in the early/middle 1960's
> the Chicago-Wabash central office -- in fact all of Chicago -- was
> either crossbar or stepping switch and you could hear it a block away
> on a hot summer night walking down the street, mainly because they
> did not have air conditioning in those days and all the windows would
> be open wide. When it started to rain, someone would go around and
> close all the windows. Quite deafening. PAT]
During busy traffic, a large stepper was much louder than a No. 5 Crossbar.