Telephone Patents

© Brooke Clarke, N6GCE



10 Feb 2005 - have replaced all the patent number links with stable URLs.

1833 Samuel Morse sends signals over wires

For about 40 years the telegraph was THE way to send a message quickly. Bell was working on a way to allow multiple messages to be sent in parallel over a single wire by using different audio frequencies for each message.  Today it would be called FDMA, Frequency Division Multiple Access.  In the process he realized that voice could be sent over a wire.  This required the invention of the microphone and the invention of the speaker.  The device in the bell patent works as both a microphone and a speaker.

See the Leclanché Battery web page for those and related patents.

Related Telegraph Patent

166095  Electrical Telegraph for Transmitting Musical Tones, Elisha Gray, July 27, 1875 178/47
Note that the Gray patent title is Electrical Telegraph for Transmitting Musical Tones not some new term to describe telephony.  Gray thought he had a patent on an improvement to telegraphy.  The single class number is 178/47 which is for Telegraphy/Harmonic or reed.

1876 Bell Invents the Telephone

First generation Local Battery operation with hand crank generator signaling.
174465 Telegraphy, A. G. Bell March 7, 1876   379/167.01; 178/48 - sending sounds over wire "The most valuable patent ever issued"
Included in this patent are the Gallows and Liquid phones. Both are combined dynamic microphone/earphone types.
The primary class number 379/167.01 is for Telephonic Communications/ Private (e.g., house or intercom) or Single Line System.
The secondary class number 178/48 is for Telegraphy/Harmonic or reed/Recorders and receivers

Gallows
                      Phone Mouthpiece
Side
                      (Gallows) view
Gallows Phone Mouthpiece
Side (Gallows) view
Is patent 174465 also the first patent for a speaker - earphone type device?  yes.
Note that the coil and terminals looks just like those used in telegraphic sounders.
For more on this phone, see my phones web page.

Remember that at the time the patent titles were commonly the same for the same patent class.  For example out of over 400 patents related to the stock ticker machines the vast majority of them are titled "Printing Telegraph".  Since patent class 379 to telephone related invensions did not exist then the only class that mase sense with 178 for Telegraph Equipment.   So although it looks strange today to see "Telegraph" as the title on a patent for the telephone, at the time it was about the only choice.

186787 Electric Telegraphy A. G. Bell Jan 30, 1877   379/167.01; 379/387.01; 381/177
In 201488 it says the rod in this patent can be a magnet.

Other Patents

199141 Telephone, E. Berliner, Jan. 15, 1878 379/167.01; 379/391; 381/178
201488 Speaking Telephone, A.G. Bell, March 19, 1878 381/163 ; 335/231; 336/110; 336/211; 381/419 -
     this is the oldest patent in class 336/110 Inductor Devices/using a permanent magnet
     The main idea is to close the magnetic path so that there is only the gap to the diaphragm.

203013 Speaking-Telegraph, T.A. Edison, April 30, 1878 381/111; 381/179
203016  Speaking-Telegraph, T.A. Edison, April 30, 1878 379/373.01
210886 Polarized Armature for Electric Bells, T. A. Watson, Dec. 17, 1878 340/397.5

Magneto Ringing Generator

202495 Telephone Call-Signal Aoaratus, T. A. Watson, April 16, 1878 379/373.01; 74/47 - Magneto & ringer
217849 magneto-electric call apparatus, George L. Anders, Jul 29, 1879, 310/75B - magneto generator (4 horseshoe magnets)

Unknown Magneto generator, missing the magnets.  Where would they go?  Is red bar supposed to be a magnet?
66A stamped on top of cast iron pole
with a 6 on either side of the hole at the top
Note only one hole at top of this pole.
Telephone Magneto
                  Generator

Telephone Magneto
                  Generator
3 holes on top of front pole.
Output is between case and shaft at center.
Telephone Magneto
                  Generator

Pole Changers

Manual telephone exchanges used electric bells as a way to get someone's attention.  These required AC at about 10 Hertz (then called Cycles Per Second or CPS).
The "pole changer" was a device that converted a DC battery voltage into AC ringing voltage.

238263 Pole-Changer for Telephone-Exchanges, E.P. Warner (Western Electric Mfg Co), Mar 1, 1881, 361/246 
685887 Pole Changer, W.F. Warner (Warner Elec Co), Nov 5, 1901, 361/246 -
    RE12162 Pole Changer, W.F. Warner (Warner Elec Co), Oct 13, 1903, 361/246 -
   
Pole Changer (20 Hz Ring Generator) Patent
                  RE12162 Fig 1 redraws by Brooke Clarke x
photo from eBay seller jonincleve
   
1067527 Signaling System, C.A. Larson (Kellog Switchboard & Supply Co), Jul 15, 1913, 379/186
1330059 Pole Changer, H.D. Currier (Kellog Switchboard & Supply Co), Feb 10, 1920, 379/181; 340/328; 340/331; 340/333 -
1382745 Electrical Rectifier and Pole Changer, F. Schoenwolf (Kellog Switchboard & Supply Co), Jun 28, 1921, 363/34; 379/418

1879 to 1890 Attempts at dial systems

215837 Telephone Switch May 27, 1879, H.L. Rosevelt 379/426
222458 Automatic Telephone Exchange Dec 9, 1879 M D & T A Connolly and T J McTighe  379/195 - dial system that did/tn work
258626 Individual Signaling Aparatus for Telephone Systems May 30, 1882 C E Buell (US Tel Mfg Co) 340/825.41; 379/177; 379/302 - early try at dial phone
275296 Automatic Signaling Aparatus for Telephone Circuits Apr 3, 1883 T N Vail 379/302; 341/192 - try that did not work for dial phone

1880 Handset

224138  Electric-Speaking Telephone R. G. Brown Feb. 3, 1880 379/433.01
250126  Speaking Telephone, F. Blake Nov 29, 1881 381/179; 381/347
250127  Speaking Telephone, F. Blake Nov 29, 1881 381/179
250128  Speaking Telephone, F. Blake Nov 29, 1881 381/178
250129  Speaking Telephone, F. Blake Nov 29, 1881 381/178
Emile Berliner and his work improving the Blake transmitter

1889 Carbon Mike

406567  Telephone T. A. Edison July 9, 1889 381/180; 252/502
AGB's patent 174465 was for a combined dynamic microphone - earphone - speaker device.  But the granular carbon mike was the common microphone used through the 1950s for telephones, military radios, and many other microphone applications.  From 1950 to the present military radios use dynamic mikes.

1891 Dial System working

Second generation system using Common Battery signaling, and sometimes common battery power for the carbon mike.

447918 Automatic Telephone Exchange March 10, 1891 A. B. Strowger 379/302   this is the class for dial systems

449106 Telephone Circuit and Aparatus, J. J. Carty, Mar. 31, 1891  379/177

1892 Carbon Mike

474230  Speaking-Telegraph, Thomas Edison, May 3, 1892 381/177
Web page devoted to this carbon type transmitter, a patent that took 15 years to grant.
485311 Telephone, A. C. White Nov. 1, 1892 381/180 - Granular Button Transmitter element assigned to American Bell Telephone
This is newer than the T.A. Edisno carbon mikes and is the one used by the millions.

1893 Bell's first patent runs out

529421 Multiple Switchboard System Nov 20, 1894 C. E. Scribner  379/319; 379/313; 379/332
545416 Telephone Aug 27, 1895 G F Shaver 379/350 - new carbon mike and improved wiring
570840 Automatic Telephone System Morgan Brooks Nov 3, 1896 379/215.01; 340/298; 340/313; 379/258
597062 Calling Device for Telephone Exchanges, A. E. Keith & C. J. Erickson, Jan. 11, 1898  379/365; 340/294; 379/367
    assigned to the Strowger Automatic Telephone Exchange, replaced the origional buttons with a dial, this is the first patent in class 379/367
670564 Telephone Receiver, C. H. North, March 26, 1901  381/393 - has internal terminals
687499 Telephone Transmitter (Candlestick), Nov 26, 1901, WW Dean, Kellogg, 381/180 ; 381/186; 381/347  - preventing carbon granules from compacting.  (found this while looking for patent 112158 which is not a Kellogg phone patent)
815176 AutomaticTelephone Connector Switch March 13, 1906 A E Keith & C J Erickson (AE Co)  379/302; 379/303 - modern step & repeat    switch, 26 page patent, very complex switch with many parts
815321 AutomaticTelephone Connector Switch March 13, 1906 A E Keith & C J Erickson (AE Co) 335/109; 74/21; 74/156; 74/169; 74/575; 379/302 - more on the step & repeat switch

831875 Interrupter for Automatic Telephone or other switches Sep 25, 1906 A E Keith (AE Co) 379/302; 379/337

848398  Automatic Exchange Selector March 26, 1907 J G Roberts (WE Co) 379/302; 335/136; 340/825.4

1508424 Telephone Desk Set Sep 16, 1924 G. K. Thompson (AT&T)  379/424; 379/436; 379/454 - dial phone with cradle for handset
1565581 Telephone Transmitter, C. H. Moore, Dec. 15, 1925 381/180 Not position sensitive
1602824 Telephone Receiver, L L Jones 381/419 ; 310/25; 367/182
1615311 Impulse Sending Device Jan 25, 1927 H. F. Obergfell   (Automatic Electric) 341/184; 379/366 - rotary dial

1642822 Calling Device Sep 20, 1927  H. F. Obergfell (Automatic Electric) 379/367; 379/369 - rotary dial

1719992 Calling Device July 9, 1929  H. F. Obergfell (Automatic Electric) 379/362; 379/367

1894 Transformer

519347  Transformer for Telegraphic, Telephonic or other Electrical Systems, M I Pupin, May 8, 1894, 379/398 ; 307/109; 333/177; 333/27; 336/182
This patent purchased by Bell Telephone in 1901.

Bakelite (Wiki)

Started looking for a replacement for shellac (Wiki) and announced Bakelite in 1909.

Patents by Leo H. Baekeland.

Design Patents

D14/149

D23825 Design for a transmitter-post for telephones, William Gray, Nov 27, 1894 - microphone only
D24175 Design for a telephone-support, Apr 2, 1895 -
D32527 Design for a telephone-standard, Apr 17, 1900 -
D41616 Design for a telephone desk-stand, William W. Bean, Jul 25, 1911 - microphone only
D43173 Design for a bottle, George R. West, Oct 15, 1912 - microphone & long pole receiver whiskey bottle
D65204 Design for a desk stand for hand telephones, George K. Thompson, American Tele, Jul 15, 1924 - A1 Mount design
D74188 Telephone Desk Stand, H.F. Obergfell, Jan 3, 1928 - center plunger hook switch, fork type support
D83514 Design for a telephone desk stand, George B. Eaton, KELLOGG SWITCHBOARD a SUPPLY CO, Mar 3, 1931 - center plunger hook switch, depressions for transmitter & receiver
D92442 Design for a telephone instrument, Everett Worthington, Jun 5, 1934 - center plunger hook switch, fork type support, spit cup transmitter, place for dial
D95765 Design for a desk stand for a hand, George R. Lum, May 28, 1935 - Bell System 302
D104087 Design for a telephone desk stand, Henry E. Billington, Kellogg Switchboard a Supply Company, Apr 13, 1937 - art deco
D109648 Design for a telephone cabinet, Theodore N. Saaty, The Screw Machine Products Corporation, executive desk control with buttons on front panel and a couple of speakers
D132902 Design for a stand for a hand telephone, Jack Barofsky, Jun 30, 1942 - art deco
D141641 Convertible desk and wall telephone set, Max G. Kolmes, Internanational Standard Electric Corp., Jun 19, 1945 - with optional hand crank
D151121 Erickson telephone desk unit, Clifford E. Erickson, Kellogg Switchboard & Supply CO., Sep 28, 1948 -
D153927 Desk Stand for a Hand Telephone, Henry Dreyfuss, Robert H. Hose, Bell Telephone Labs, May 31, 1949 - Bell System 500 Calls D95765 & D151121
D159188 Telephone Set, Hiram D. CurrierLeich Electric Company, Jul 4, 1950 - a 302 telephone with the dial replaced by a hand crank?
D210776 , D210777 Telephone stand, Henry Dreyfuss, Bell Telephone Labs, Nov 19, 1957 - Princess



Newer Patents

4823379 Telephone ringer 379/373.01 ; 340/397.5 - This is an example of something that looks like a good idea.  BUT . . . the way it's been manufactured it's so fragile that age or dropping the phone breaks the plastic parts.  So professional phone installers avoid any phone that contains this ringer like the plague.

Cross Bar Switch replaces the Step and Repeat Switch

Third generation switching, didn't last that long

Electronic Switch replaces the Cross Bar switch

Forth generation, and now current, switching.

USPTO Classification Numbers Relating to "Telephone"
Telephone ..................................
  379
    Answering device   
        Answering-recording system .........  D14 / 141
        Calling number recorder ............  379 / 142.01+
        Remote inquiry .....................  379 / 76
        Sound recorder or reproducer .......  379 / 70+
    Attachment .............................  379 / 441+
        Base pad ...........................  248
        Index ..............................  40 / 336+
        Pad ................................  281 / 44
        Roll type pad ......................  281 / 11
    Automatic systems ......................  379 / 258+
        Call ...............................  379 / 350+
            With recorded message ..........  379 / 69
        Card ...............................  40 / 336+
        Common control .....................  379 / 268
        Party line .........................  379 / 182+
    Booths .................................  52 / 27+
        Design .............................  D25 / 16
        Movable wall .......................  52 / 71
    Calling ................................  379 / 352+
    Card attached to telephone .............  40 / 336+
    Cellular or zoned radiotelephone .......  455 / 422.1+
    Coin collectors for pay stations .......  194
    Coin operated ..........................  379 / 143+
    Computerized switching .................  379 / 284
    Cordless ...............................  455 / 462+
    Design .................................  D14 / 142+
    Dial  
        Dial structure .....................  379 / 362+
        Illuminated ........................  362 / 24
        Locking ............................  379 / 445
        Pulse transmitter ..................  379 / 362+
        Self luminous ......................  40 / 337
        Telephone system ...................  379 / 258
    Directory ..............................  40 / 371
    Earth transmission .....................  455 / 40
    Handset ................................  379 / 433.01+
    Headgear support .......................  379 / 430
    Key systems ............................  379 / 156+
    Light wave telephony ...................  398 / 132+
    Lights for telephones ..................  362 / 88
    Mechanical telephones ..................  181 / 138
    Message counter ........................  379 / 139
Muffler for mouthpiece .................  181 / 242
    Over composite line used for ...........  379 / 90.01+
    Other services .........................  379 / 90.01+
    Pad or book holder combined ............  248 / 441.1+
    Party line .............................  379 / 177+
    Plural phone systems ...................  D14 / 241
    Push button call transmitters ..........  379 / 368+
    Radio transmission .....................  455
    Receiver and transmitter combined ......  379 / 433.01+
    Repeaters ..............................  379 / 338+
        Dial pulse .........................  379 / 341+
            Conversion .....................  379 / 339
        Voice frequency ....................  379 / 338+
    Repertory dialers ......................  379 / 355.01+
    Sets ...................................  379 / 419+
    Sterilizer .............................  379 / 439
    Supports ...............................  379 / 454+
    Switchboard ............................  379 / 319+
    Switches ...............................  379 / 422+
    Telemetry ..............................  128 / 904*
    Toy telephones .........................  446 / 141
        Design .............................  D21 / 517
    Train telephony ........................  246 / 7+
    Transducers ............................  379
Class 381 Electrical Audio Signal Processing Systems and Devices
Telephone Microphone.................... 381/355
231226 Telephone Transmitter Aug 17, 1880 G. M Hopkins 381/166; 381/355
          202870 Speaking-Telephone Transmitter April, 23, 1878 G. B. Richmond 381/166

        652230 Art of Reducing Attenuation of Electrical Waves  and Aparatus therefor  June 19, 1900  M. I. Pupin - Loading Coil



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