The 711B was donated to the engineering school back in the late 60's, and somehow found it's way to the station, where the station engineering department installed it, much to the annoyance of the telco (Pacific Telephone at the time).
The 711B was served directly by telco for many years, and was finally placed behind the campus PBX (NorTel SL-100) about 15 years ago, in order to take advantage of the school's bulk long distance rates, and extended local area dialing, and long distance access control and accounting.
The 711B was in service for about 15 years before Stanford installed the SL-100, before that the campus was served by Centrex, giving KZSU the distinction of being "Stanford's Oldest Independent Telephone Company"
The 711B had a few special hacks, including the ability of certain special extentions to connect to other extentions without battery present on the circuit, allowing for audio feeds to be setup thru the switch. There were bandwidth restriction due to the various transformers and coils in the circuit, but it worked.
There were about 100 extentions in service, out of 200 available. It has been downsized in the last few years to make room for a donated NorTel PBX, that has yet to be placed in service due to software issues.. I think they just removed a bunch of selectors, etc that were never used.
1890's technology, manufactured in the late 1950's, installed in the laste 1960's, and still in service in 2005. Hows that for longevity.
Currently, audio feeds on campus are patched directly on the main patchbay as dry pairs.
