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September Singing Wires is now available in the members login area.

Telephone Collectors International is an organization of telephone collectors, hobbyists and historians who are helping to preserve the history of the telecommunications industry through the collection of telephones and telephone related material. Our collections represent all aspects of the industry; from the very first wooden prototypes that started the industry to the technological marvels that made the automatic telephone exchange possible.

If any of this interests you, we invite you to join our organization. Look around and see what we have to offer. Thanks for stopping by!

Telephone Collectors International
3805 Spurr Circle
Brea, CA 92823

Sample from the September 2014 Singing Wires
Building a 500-Series Wall Keyset

Ever since I saw the picture of a prototype 1A2 keyset based on the 554 wall telephone on Paul Fassbender's excellent site, I have wanted one. Knowing there's about zero chance of finding an example, I decided to try and make one! Although true purists will probably scoff at my idea, I'm quite pleased with the results, shown on the right in Fig.1 along with the photo of the Western Electric F-55341 rom Paul's site.

First, I needed a donor 554. They're pretty plentiful and inexpensive. Next, I needed a set of round buttons and the designation strip for them. Fellow collectors were quick to respond to my request for these items (Fig. 2). A standard key and mounting cord from a donor 564 set was needed too, again the collecting community came through. After taking some quick measurements it was determined the key would fit the 554 housing, but the existing network and ringer would have to be relocated or removed. The mounting tabs for......

For the rest of this story along with many others, access to our Bonus Pages which contain many more photos, online access to all back issues of Singing Wires from 1986 on and many other benefits, join our club. It's easy and it's not expensive.

Sample from the July 2014 Switchers' Quarterly
Trunking in the Ericsson AGF Switching System
By Chris Mattingly

The system is based on switches that can select one of 500 positions in two motions. Rows of phosphor bronze bars the diameter of pencil lead are arranged in straight rows (called a "frame") in a semi arc running up and down the equipment rack. The contact wipers are mounted as such that they can rotate around 90 degrees one to 25 positions then extend in to a row of bars one to 20 positions, for a total of 500 positions.

Each office can grow to a maximum of 10,000 lines. Twenty frames are needed on the selector to access the connector switches needed to access 10,000 lines. That leaves five frames for trunks to other offices or 10,000 line groups in the same office. In figure one, a diagram of the selector frames is shown. The wipers are idled on the left side of the frames and they rotate clockwise, or to the right. The first five positions are for access to trunks and the remaining 20 are for the connectors. Each rectangle on the diagram represents a frame, the set of bars needed for 20 positions, which are wired to switches downstream from there. The wipers stop at the desired position, under the control of the register. The switch then extends the wipers into the frame and stops on the first idle position to seize a switch in the downstream rack.

Figure two shows a simple diagram for a 500 block of lines. There would be 20 of these for a 10,000 line office. For an office this size.....

Our Journal for those interested in telephone switching systems, both old and modern. For the rest of this story and online access to all back issues, join our club and add the Switchers' Quarterly option for $5 a year more.

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