KOB stands for Key On Board. A KOB has a key and a sounder mounted on a single base. The first KOBs appeared in the 1860's. Before that, the individual components of a telegraph office, such as the key, sounder, and relay, would be mounted separately on the operator's table.

Some KOBs were designed to be simple practice sets for learning Morse Code, while others were actually used in telegraph offices. Box Relays were likely the earliest type of KOB to be used in telegraph offices. With a Box Relay, the sounder electromagnets are enclosed in a wooden box that was mounted on the wooden base with a telegraph key. The box acted as a sound amplifier.

Other KOBs were used in large homes as communication devices between rooms. These were known as Private Line Sets, or PL Sets. Most were made of cast iron with only the moving parts made of brass, and were ornately painted in order to fit in with the Victorian style in the home.

In Europe, especially in Germany, it was common to see a different version of the KOB, in which a key and a tape register were mounted on a single board.

Below are some pictures of KOBs dating from the 1860's up to the early 1900's. Click on each thumbnail to view the full size image:

James Clark Box Relay, Philadelphia. Ca. 1860's The Camelback Key on the Clark Box Relay J.S. Keeling Box Relay, NY. Ca. 1865 Charles T. & JN Chester, NY. Ca. 1860's
Henning Box Relay. Ottawa, Illinois. Ca. 1860's Another View of the Henning Box Relay Top View of the Henning Key Henning Name Stamped on Armature Frame
G.M. Phelps Combo Set, NY. Ca. 1860's Charles Williams, Boston. Ca. Late 1860's L.G. Tillotson Splitdorf Patent Box Relay, NY. Ca. 1870 Lake Shore & Michigan Southern Railway Box Relay. Ca. 1870
W.H. Johnson Combo Set. Louisville, Ca. 1870 Charles Williams, Boston. Ca. 1870 Charles Williams, Boston. Ca. 1870 Bliss-Tillotson "Cheapo" Practice Set, NY. Ca. 1870
L.G. Tillotson Box Relay, NY. Ca. 1870 LG Tillotson Relay With Caton-Pattern Key. Similar to the Splitdorf Patent Box Relay but Minus the Resonating Box. Ca. 1870   Tillotson Practice Set. Ca. Early 1870's
Box Relay by George Bliss, Chicago. Ca. 1870 Close-Up of the Caton-Pattern Key (With Snapper Circuit Closer) on the Bliss Box Relay George Bliss Practice Set, Chicago. Ca. Early 1870's Knox & Shain, Philadelphia. Early 1870's
KOB Made by Louis Schaefer in Japan. Ca. Early 1870's Another View of the Schaefer KOB Charles Williams, Boston. Early 1870's Electrical Construction Co, San Francisco. Ca. Early 1870's
Late Charles Williams KOB, Boston. Early 1870's Top View of the Williams KOB Partrick-Bunnell, Philadelphia. Early 1870's Co-Operative Mfg. Co, Philadelphia. Ca. 1870's
Early Western Electric Private Line Set, Chicago. Ca. Early 1870's Partrick & Carter PL Set, Philadelphia, Ca. 1870's L.G. Tillotson PL Set, NY. Ca. 1870's Western Electric Lewis Key PL Set. Ca. 1870's
Ornamental Paint Variations on Western Electric Lewis Key PL Sets Altoona Shops Box Relay, Altoona, PA. Ca. 1870's Watts PL Set, Baltimore. Patented 1872 Another View of the Watts PL Set
Watts Practice Set, Baltimore. Ca. 1870's J.A. Lannert, Cleveland. Ca. 1870's M.A. Buell, "Eureka" Practice Set, Cleveland. Ca. 1870's Cast Iron Private Line Set by Jerome Redding, Boston. Ca. 1870's
R.K. Pearce Private Line Set, Philadelphia. Ca. Late 1870's R.K. Pearce Combo Set, Ca. Late 1870's Partrick & Carter Combo Set, Philadelphia. Ca. Late 1870's Western Electric Box Relay with Lewis Key, NY. Ca. Late 1870's
J.H. Bunnell, NY. Late 1870's Altoona Railroad Shops, Altoona, PA. Ca. Late 1870's M.A. Buell, Cleveland. Ca. Late 1870's A.B. Lyman, Cleveland. Ca. Late 1870's
Another KOB by M.A. Buell, Cleveland. Late 1870's Close-Up of the Buell Key Jerome Redding, Boston. Ca. Late 1870's L.G. Tillotson Practice Set, "The Home Telegraph Instrument", NY. Ca. Late 1870's
Thomas Hall "Washington" Set, Boston. Ca. 1880 Tillotson Combo Set With Phillips Key, Ca. 1880 California Electrical Works, San Francisco. Ca. 1880 Electrical Supply Co, San Francisco. Ca. 1880
Partrick & Carter, Philadelphia. Ca. 1880 Altoona Shops Cain Set. Ca. 1881 Jerome Redding, Boston. Ca. Early 1880's Jerome Redding KOB With Camelback Key. Ca. Early 1880's
Partrick & Carter, Philadelphia. Ca. Early 1880's Viaduct Mfg. Co, Baltimore. Ca. 1884 AF Fleischmann, Philadelphia. Ca. 1884 Another View of the Fleischmann KOB
E.S. Greeley Box Relay with Victor Key, NY. Ca. 1880's Electrical Supply Co, NY. Ca. 1880's C.H. DuBois Box Relay, NY. Ca. 1880's Utica Fire Alarm Co. Ca. 1880's
J.H. Bunnell Box Relay, NY. Ca. 1880's California Electrical Works, San Francisco. Ca. Late 1880's British GPO Baseboard Set. Ca. Late 1880's E.S. Greeley Ludwig Instrument, NY. Ca. Late 1880's
New Haven Clock Co. Key-Sounder Set. Ca. 1888 New Haven Clock Co. Ca. Late 1880's Western Electric Box Relay, Chicago. Ca. Late 1880's A.B. Lyman, Cleveland. Ca. Late 1880's
Western Electric PL Set with Steiner Key, Chicago. Ca. Late 1880's Western Electric Box Relay with Steiner Key. Ca. Late 1880's Western Electric Steiner KOB. Ca. Late 1880's E.S. Greeley, NY. Ca. Late 1880's
Shaw Electrical KOB. Ca. Late 1880's J.H. Bunnell Practice Set, NY. Ca. Late 1880's Early Portable Japanese Key & Register Set, Oki Japan. 1890 Altoona Shops KOB, Altoona Pennsylvania. Ca. 1890
Altoona Shops KOB, Altoona Pennsylvania. Ca. 1890 Novelty Electric Co, Philadelphia. Ca. 1890's American Electrical Works, Cleveland. Ca. 1890 I.H. Moses, Cleveland. Ca. 1890's
Another View of the Moses KOB Western Electric Box Relay with Rod-Lever Key. Ca. 1890's Western Electric Combo Set, Chicago. Ca. 1890's Knapp Electrical Works, Chicago. Ca. 1890's
German Key & Relay Set. Ca. Late 1800's British GPO Key, Sounder & Galvanometer. Ca. Late 1800's J.H. Bunnell Barclay Box Relay, NY. Ca. 1890's Western Electric Barclay Box Relay, Chicago. Ca. 1890's
J.H. Bunnell Combo Set, NY. Ca. 1890's A Very Small Bunnell KOB in Metal Box Used by The US Army During the Spanish-American War. Ca. 1898 Close-Up of the Bunnell Military KOB Small KOB With Barclay Box Relay Marked "N.T.Co" (Northern Telegraph Co.)
Another View of the Small Barclay Box Relay. Note the Key is the Same as on the Bunnell Military KOB Austrian Key, Register & Galvanometer Set. Ca. 1900 Gem Practice Set, Horace Martin, NY. Ca. 1903 Novelty Electric Mini KOB, NY. Ca. 1904
Novelty Electric KOB with Regular Size KOB German Key & Sounder Set. Ca. Early 1900's Postal Telegraph Skirrow Patent KOB, NY. Ca. 1904 Ohio Transmitter Co. Practice Set. Ca. Early 1900's
J.H. Bunnell Ghegan Patent KOB, NY. Ca. 1905 Foote-Pierson Compact KOB, NY. Ca. 1905 Foote-Pierson Practice, NY. Ca. Early 1900's KOB by MESCO (Manhattan Electric Signal Co), NY. Ca. Early 1900's
Another View of the MESCO KOB Small Bunnell Practice Set. Early 1900's J.H. Bunnell KOB with Pennsylvania Railroad Keystone Tag, NY. Ca. Early 1900's Nickel Plated Bunnell KOB, NY. Ca. Early 1900's
Bunnell Mini KOB. 1.5" wide. Ca. Early 1900's Bunnell Navy KOB, NY. Ca. Early 1900's European Mini KOB. Maker Unknown. Ca. Early 1900's L.M. Ericsson Swedish KOB. Ca. 1919
Bunnell Beeko Practice Set. Ca. 1919 Side View of the Beeko Set Signal Electric R-68 Practice Set With Buzzer and Morse Code Plate Close-up of the R-68 Buzzer
Signal Electric Sheet Metal Key & Buzzer Practice Set J-38 Practice Set by Fred Cramer Canadian RCAF Key & Buzzer Practice Set. Wilson Mfg. Co, Toronto  



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