top of page

Switching Devices 

icon for more info

This section is a review of the many switching devices invented for use in telephone exchanges. Primarily, the coverage is focused on the switch mechanics; how it works. A given switch is used multiple times in the fabric that creates the talking path end-to-end.  The switches are designed to route the "talking path", usually 2 or 3 wires per connection. One exception is is the "Sequence+" switch in the diagram below. Explore it to see its function. 

Don't confuse the switch name with it's sometimes namesake exchange. For example a crossbar switch is used in the Crossbar exchange. To appreciate how a given switch integrates into an exchange, see the
master diagram on the Exchange Anatomy page.

The switch names in the diagram/menu are categorized based on what movements they use to make a connection; either linear motion, radial motion, both, or some other ways. So, most switches have either one or two degrees of freedom for moving its connecting arms to make a circuit.

This is not an exhaustive list. However, the ones here are either important because of their proven success or pure ingenuity. The hierarchy implies at least some inheritance nature. For example, the devices below "First Strowger" are influenced by this design. Also, the ordering, top to bottom, is by date, first to last (approximately). 
 

Select the (i) near a switch name to explore its nature. The switch coverage includes commentary, images and often one or more videos.  Again, the scope is on individual switch mechanics and not about how calls are made in an exchange. 

Master diagram showing links to 15 telephone switch types - ordered by movement type

This section is for mobile device navigation and has the same choices as the graphical navigation for desktop browsers. The switch coverages include commentary, images and often one or more videos.  The scope is on individual switch mechanics and not about how calls are made in an exchange. 

Linear:
Bell System Panel
Fallwahler


Rotary:
Connolly
Lorimer
Solo Rotary
Bell System 7A Rotary


Linear + Rotary:
First Strowger
Keith's Zither
Keith's Strowger
Ericsson 500 
Keith's Plunger line switch
Ericsson XY


Other methods:
All-Relay
Crossbar
Sequence switch
Peculiar 

bottom of page