Of course no desk is complete without a spittoon.

Telephone central offices are still battery powered but with wet cells, not the dry cells pictured above. The power to your land-line phone is 48 volts direct current. Ringing voltage is 105 volts alternating current (20 cycles).

The reason batteries are used is so the phone system can continue operating in the event of a power failure.

The thing under the table that looks like a giant ignition distributor -- what is it?

The banks of #6 ignitor cells on the top shelves appear to be wired up in groups of 30 cells (15 each in two rows front-to-back), which would make the necessary 48V to power a telephone system. They'd use batteries so the students could play around without breaking the actual phone system.

The thing at the left is a test set. I can make out the words OSCILLATOR and FILTER on the central switch bank. The round items at the top are early vacuum tubes, so it has actual electronics in it.

The wiring panel on the right appears to be part of infrastructure for the building. It connects to the main trunk lines via the fat cable in the middle, and the smaller wire pairs are for individual phones.

Those huge metal lumps under the table (in the middle of the photo) might be used for pressurization of buried cables.

What do you suppose is in that bottle on top of the bookcase?

[Ink. - Dave]

I think it's a classroom. The in-box on the desk is labeled "experiments," and those look like people studying rather actually working. I suspect the equipment you see is a small scale, and probably self-contained, telephone system used for teaching.

in the "Central Place Theory" pattern.

That wiring panel thing on the right wall is a direct ancestor of the wiring done for our new server at work.

It looks like there are a whole bunch of batteries involved in the operation of this telephone company. Surely a knowledgeable Shorpster knows this and can identify the other equipment in this fascinating photo.