Some emailed ideas about the "Switchboard" picture

Dear Mr. Marnell
I was looking over the first picture in your photo gallery where you had the comment "Any Ideas?" The system he is looking at is an older signaling device that is still in use in some areas. It uses a system called a "McCullough Loop" (Sorry, but I don't know the correct spelling for McCullough). This loop is basically a single telephone line that is linked from site to site with a transmitter at each site. When the alarm is tripped at that site, the transmitter signals a series of signals (similar to a telegraph key). This way the person at the other end can  tell which site on the loop sent the signal. Later versions of this system had the receiver using ball point pen refills on a strip of paper (he is looking at the strip of paper). The pen continually rests on the paper, but when a signal is sent in there the pen jumps up on the paper, thus creating a series of blips in the lines that can be read. When I was working in the burglar alarm industry in the early 70's we used a system similar to this. This saved a lot of money because a different telephone line did not have to be added for each site that was being monitored.

    So, on the same telephone looped line you could have a many transmitters as you had possible combinations of blips. For example a 1-1-1 could be easily differentiated from a 2-2-2. But also there are lots of other combinations possible, such as 1-1-2, 1-2-1 and 2-1-1 and so on.    Also, in the burglar alarm industry the number of times the sequence repeated also provides information. For example, if the sequence repeated three times that meant either the alarm went off or the company representative was arriving for work in the morning and tripped the alarm. When they closed down for the night, it would repeat twice. This way, the alarm company would know that the alarm was set for the night.

A lot of fire departments back east used this system for their pull-boxes. If a signal box were pulled by a citizen, then a signal would be sent identifying where it was sent from. The town where I lived had volunteer firefighters, so in addition to the signal being sent to the main station, a large horn blared out the sequence of information so that volunteers could go directly to that location without having to check in with the station. This was very effective, but usually woke up the whole neighborhood.    Hope this may help you. I assume that the system in the picture was used similarly, either for burglar/fire alarms or to signal where assistance was need through the use of pull-boxes.Jim Kuthy

James E. Kuthy
Police Consulting Division Manager/DPAC Test Development Manager


Regarding the first photo in the Photo Gallery captioned, "Los Angeles Policeman at Switchboard."

I am not sure what that piece of equipment is but here is my speculation (most likely not true but what the heck):

The equipment shown is one of the first digital computers. This particular unit was developed for automated multi-parameter evaluation of Los Angeles city coffee and donut shops patronized by LAPD officers. This was an attempt to determine the best donut shops in the city based on location, pricing, quality of donuts, goodness of coffee, accessibility to the shop
(i.e. can you easily pull out on to the highway in a hurry if responding Code 3), and other aspects, for example, is the shop in a good area so to have benefits like community relations and sponsoring PAL activities.

This was quite ambitious for the time so the system was abandoned. However, with the growing aerospace companies in southern california such as Lockheed, Northrop, and Douglas saw the potential in such tools which they started working on these in the 1930s. Although what these companies did was leasing business machines from IBM and modifying them to do calculations, which was a major event in the history of computers.

The question is... has anyone re-visited the development of a donut shop evaluation program?

- Michael W


"Now for some real information on that picture. It is not a communications switchboard. The knife switches on the left are for electrical power. The panel on the right is a drum cam timer. The officer is pointing with his finger to the cam follower arms that turn on and off switches as the drum rotates and the cams on the drum move the following part of the arm up and
down as the cam diameter changes. The round cylinder with perforrations above the drum timer is the motor that turns the drum. It is connected to the drum by the two large gears on the side. The unit on the shelf below by the officer's elbow is unknown since the picture is out of focus. This is pretty standard equipment for that era. It was used for many decades. In a
way, this apparatus is very much the predecessor to the early relay based digital computers.

"As to purpose I cannot say. However, I am sure that such items were used in the baking of donuts and other time sequential manufacturing processes."

You ask about the "Switchboard" shown. Looks to me like he could be standing in front of a couple of Gamewell
telegraph recorders. See the reels? Rolls of paper are fed through a punch. You can read the holes to which callbox had signaled.

For example, if you inserted and turned your key in the hole in the center of the front of the callbox shown in
http:/ (between the words "Police" and "Telegraph"), the box would send the box number to the recorder.

Box "1 1 3" would show up as ". . ...".

Officers would document that they were patrolling where they were supposed to be by doing a "wind" as they passed the box.

The fire departments use (used) a similar system. When you pull the hook inside the fire box, the box number is sounded ("tappped out") in the fire alarm center (and the individual fire station "tap rooms".

Here's how they work:

You may find these discussion interesting:

ON THE OTHER HAND... What look like reels could be magnetos.



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