Sounders & Relays

(Post-1880)

 

A telegraph relay is basically a switch that is controlled by an electromagnet. A telegraph signal present on the line would energize the electromagnets, causing a steel armature plate to move and toggle a lever between one or more sets of electrical contacts. They were most often used to connect between a local telegraph circuit (key and sounder) and the main telegraph line. As telegraph systems became more complex, with multiplex systems etc, the relays became more complex as well. Relays can be distinguished from sounders by the presence of at least 2 sets of terminal connections. Sounders (with some exceptions) only have one set of terminals, since they were generally not used to switch between different circuits.

The telegraph sounder was developed after it became clear that operators were able to read the incoming telegraph signal by listening to the clicking sound produced by the telegraph register. The sounder was able to greatly amplify this clicking sound with various improvements in the acoustics of the instrument.

When the sounder lever is pulled down, it strikes against a metal post called an "anvil", which creates a sound. Many of the early anvils were just simple machined metal posts, which were not the best designs from an acoustics standpoint. So, some of the early sounder designs by instrument makers such as Charles Chester and Charles Williams employed an acoustic base, where the wooden base was hollow with a hole in the top or bottom to act like a resonator, much like a guitar. This helped amplify the sound.

With other later designs, the brass base on which the anvil and other parts were mounted was itself hollow, which also helped act as a sound amplifier. There were even designs where the anvil looked like a metal drum (see the Gilliland Drum Sounder below), providing even more sound amplification. Eventually though, the sounder settled on a common design with a hollowed brass base and a 2-legged anvil. This progression can be seen as you browse through the photo gallery below.

The exact date when telegraph sounders came into use is not known, but it is believed the first sounder was invented by James Clark & Co. from Philadelphia around 1856. There is a simple sounder that appears to have been created by modifying a relay in the collection of the Smithsonian Museum. A picture of this sounder can be seen in the photo gallery on this page.

Below are some pictures of Sounders and Relays dating from the 1850's up to the early 20th Century. Click on each thumbnail to view the full size image:

Western Electric Split-Anvil Sounder. Ca. Early 1880's California Electrical Works, San Francisco. Ca. 1880 Altoona Shops Cain Sounder. Ca. 1881 JH Bunnell Sounder With 1882 Patent Base.
A.B. Lyman, Cleveland, "Bullnose" Sounder. Ca. Early 1880's Another View of the Lyman Bullnose Sounder Stearns & George, Boston. Likely a Reseller of Instruments, Not a Maker Unmarked Western Union Style Relay
Another View of the Unmarked Relay Partrick & Carter, Philadelphia. Ca. Early 1880's William Davis Vertical Sounder, Jersey City. Ca. 1883 Gilliland Drum Sounder. Made by James Gilliland, Indianapolis Indiana Ca. 1885
Another View of the Gilliland Drum Sounder Viaduct Mfg, Baltimore. Ca 1880's P.B. Delaney Sounder, NY. Ca. 1880's Western Electric Box Relay, Chicago. Ca. 1880's
Jerome Redding, Boston. Ca. Late 1880's New Haven Clock Co. Sounder. Ca Late 1880's New Haven Clock Co. Relay. Ca. Late 1880's Lewis & Fowler Mfg. Brooklyn NY. Ca. 1886-1887
Altoona Shops Sounder. Ca. Late 1880's C.H. DuBois, NY. Ca. Late 1880's British GPO Sounder. Ca. Late 1880's Sounder by Standard Electric, Louisville, KY. (Matching Sounder for the Biggs Key)
The Standard Electric Sounder Has an Unusual Single-Piece Frame and Anvil British GPO Phelps-Style Sounder. Ca. 1880's E.S. Greeley Relay, NY. Ca. Late 1880's E.S. Greeley Pole-Changer Relay. Pat. 1888
Another View of the Greeley Pole-Changer Relay JH Bunnell Repeating Sounder, NY. Ca. Late 1880's A.B. Lyman "Rock Bottom" Sounder, Cleveland. Ca. 1890's A.B. Lyman Leaf-Spring Pivot Sounder, Cleveland. Ca. 1890's
Another View of the Lyman Leaf-Spring Pivot Sounder J.H. Bunnell Pole-Changer Relay. Ca. 1890's Western Electric, Chicago. Ca. 1890's Greeley Pony Sounder, ES Greeley, NY. Ca. 1890's
Greeley Victor Relay. Ca. 1890's Western Electric Tube-Lever Sounder. Ca. 1890's Western Electric Pole-Changer Relay. Ca. 1890's Another View of the Pole-Changer Relay
Close-Up of the Relay Mechanism Western Electric Tube-Lever Repeater. Ca. 1890's Another View of the Tube-Lever Repeater Milliken-Hicks Repeater. JH Bunnell, NY. Ca. 1890's
Another View of the Milliken-Hicks Repeater E.S. Greeley Double Relay, NY. Ca. 1890's California Electrical Works Relay, San Francisco. Ca. 1890's Francis Hatmaker. Ca. 1900
J.H. Bunnell Giant Sounder A Double-Relay Instrument That Was Actually Used as an Automatic Transmitter for Undersea Cable Telegraph Systems. Muirhead & Co. London. Ca. Early 1900's Close-Up of the Cable Transmitter Unit Pocket Watch Sounder. M&L.E.Co. NY. Ca. Early 1900's
The Back of the Pocket Watch Sounder Showing the Name Inscription Belgian Relay. Ca. Early 1900's Belgian Drum Sounder. Ca. Early 1900's Austrian Relay. Ca. Early 1900's
German Relay. Ca. Early 1900's British GPO Sounder in Resonator. Ca. Early 1900's Bunnell Polar Relay. Ca. 1900 Western Electric Polar Relay. Ca. 1900
Bunnell Ghegan Patent Sounder. Ca. 1905 Bunnell Ghegan Sounder (Different Version) Ca. 1910 Western Electric "Gooseneck" Relay. Ca. Early 1900's British A.T.M. Relay. 1918
Tillotson Sounder Converted to Spark Relay Bunnell Mini Sounder. Ca. Early 1900's Foote-Pierson. Ca. Early 1900's Bunnell Secret Sounder. Ca. Early 1900's (Sounder Inside Headphone)
Inside the Secret Sounder Mascot Resonator Hood With Sounder Standard Resonator Hood Swing-Arm Resonator Hood
Bunnell Mainline Sounder, 1895 Patent. Ca. Early 1900's Another Version of the Bunnell Mainline Sounder MESCO Sounder. Ca. Early 1900's Western Union Type 3-B Sounder. Ca. Early 1900's
Western Union Type 3-C Sounder. Ca. Early 1900's Western Union Type 15-B Mainline Sounder. Ca. Early 1900's Western Union Type 21-A Relay. Ca. Early 1900's Western Union Portable Telegraph Set. Used by Telegraphers at Live Events Like Baseball Games, Etc.
Another View of the Western Union Portable Set Western Union Type 7-A Sounder. Ca. Early 1900's Signal Electric Sounder, Menominee, Michigan. Ca. 1920's Signal Electric Relay. Ca. 1920's
Art Deco Style Swedish Relay. Ca. 1920's Japanese Sounder Allegedly Destroyed by Shrapnel During WW2 Nameplate Indicates Sounder was Made by Youhin Seijoujo in the Year Taisho 3 (1915) A Very Late Japanese Sounder Made by Toubu Denki, 1950
     
  Close-Up of the Toubu Denki Nameplate    

 

 

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