is to demonstrate the social and technical significance of the telephone network from 1876 to the present, using working equipment to provide tangible, operable evidence of an evolving technology.
the inventiveness, craftsmanship, ingenuity and industry of the telecommunications community through educational programs, exhibits, and special events.
"It's for YOU"
The Telephone Museum is home to many pieces of telecommunications history. Many of these items are static displays, but the Museum also has a sizeable quantity of restored, working equipment.
In addition to examples of various types of telephones from the last sixty years or so, the Museum is home to a number of complete switching systems of different vintages. There are manual switchboards of both the Magneto and Common Battery variety; there are demonstrations of the Strowger automatic switching system as well as complete Strowger exchanges. There are complete Crossbar systems as well as a North Electric all-relay system. All of the working telephone systems are interconnected to represent a regional telephone network as it might have existed some forty or fifty years ago.
All of the Museum's working switching systems have live, working telephones connected to them. As you tour the various displays, feel free to pick up a phone an make a call! Instructions on how to make calls from each telephone are available at the Museum.
The Telephone Museum is home to a number of restored manual switchboards of both the Magneto and Central Battery type. You can make and receive calls on these switchboards; you can also experience what is was like to be a phone company operator working these boards!
The Strowger System was invented by Kansas City undertaker Almon Brown Strowger in the late 1880's. Legend has it that Strowger believed that unscrupulous telephone operators were steering business to his rival. Determined to remove the operators from the equation, Strowger invented a system that would be the mainstay of automatic telephone switching for the next one hundred years.
The Strowger system was, at one time, probably the most widely used automatic telephone system in the world. It was popular with the independent telephone companies in North America, as well as in Great Britain (and the British Colonies.) It was later adopted by the Bell System as an easy way to replace overloaded manual switchboards; Bell could buy off-the-shelf components from the companies that were already building systems for the independents.
At The Telephone Museum you can see examples of Strowger equipment made by the Automatic Electric Company, who bought the original patents from Strowger. Click here to see pictures of Strowger systems at the Telephone Museum.
One of the problems faced by the designers of Strowger selectors was that the contacts that carried the telephone circuit from one switching stage to the next tended to become tarnished and thus cause noisy connections. There was little that could be done about this; the design of the switch was such that it was only practical to use what's known as base metal contacts for the selector banks. Some telephone manufacturing companies tried to overcome this problem by designing systems that used relays instead of two-motion selectors for switching telephone calls. Relay contacts could be manufactured with small amounts of precious metals such as gold and platinum, which gave a more reliable, less noisy connection. (Companies designing such systems also avoided paying license fees on Strowger's patents.)
At The Telephone Museum you can see an example of this type of system. Made by the North Electric Company, this is their type CX-100. The 100 in the model number means that the system can accomodate up to 100 telephone subscribers. North Electric also made smaller and larger versions of their CX switches. The Museum's CX-100 was originally installed on the island of Frenchboro, Maine, where it served a few dozen subscribers.
Telephone service in Frenchboro was formerly run by the Island Telephone Company; when that company was sold to another independent telephone operator and a new digital switch was installed, Island Telephone generously donated the telephone switch, together with the building that housed the switch, to The Telephone Museum. The Museum also owns the microwave radio system that linked the island with the mainland, but the microwave is no longer funtioning. You can, however, still make calls to and from the CX-100 system that served the insland's inhabitants for many years. Click here to see pictures of North Electric CX-100 system at The Telephone Museum.
A further problem with the Strowger system was that a lot of relays and other equipment in each switch were used in setting up a call, but were no longer needed once the call had switched through to the desired party. Telephone switch designers therefore started to develop what are known as Common Control systems, whereby the relays used to set up the call (known as common equipment) could be shared by many calls. Once the common equipment had set up one call, it was free to be used on the next call. A much smaller amount of equipment was then needed just to keep the call connected while the two parties were talking.
Further research into the design of relay-based telephone switches and common control systems led ultimately to the development of the Crossbar Switch. Although a primitive form of crossbar switch had been designed back in 1915, it wasn't until the 1930's that viable systems entered public service, in the U.S. and in Sweden. In the U.S., Bell Telephone Laboratories developed the No. 1 Crossbar System to serve large metropolitain areas and the first No. 1 Crossbar exchange opened in New York City in 1937.
Bell Labs continued to develop crossbar technology, culminating in the design of the No. 5 Crossbar exchange, which first entered service in the 1950's. The Telephone Museum is home to representative sections of a No. 5 Crossbar system that served the town of Belfast, Maine until the 1980's. Although the Muesum owns enough parts to make a working No. 5 Crossbar system, that system is still undergoing restoration and is not yet operational.
The Museum also owns a complete No. 3 Crossbar system that formerly served the town of Bradford, Maine. This system was obtained with the generousity and cooperation of the former New England Telephone Company when the Bradford exchange was converted from crossbar to a new digital switch. The No. 3 Crossbar was originally delivered to local telphone companies as a self-contained unit on a steel palette. This fact meant that the Museum was able to aquire the entire switch, still on its palette and in a still-funtional condition. When the switch arrived at the Museum, it was only necessary to connect some telephones and a source of electric power to bring the exhibit to life.
Today you can make and receive telephone calls on The Telephone Museum's No. 3 Crossbar switch, and you can listen to the unique sounds that the switch makes as it connects your calls. Click here to see pictures of The Telephone Museum's Crossbar switches.