Even the smallest of telegraph key or antique radio collections has at least one and probably several telegraph keys with a long string of letters and numbers. If the string starts with a 'C' or 'SE' is is most likely a Navy key. A typical number on a Navy key would be CTE-26003A, CT-1756 or SE-68A. The former is a flameproof key from the W.W.II era made by Telephonics. The next is a key from an arc transmitter from the post W.W.I era made by Federal Telegraph and the later a spark key of the early W.W.I era made by the Boston Navy yard. How does one learn this type of information from the numbers?

The Navy "Type Number" system of equipment nomenclature was introduced by the Navy's Bureau of Steam Engineering in 1915 or 1916. (References do not agree on the date.) The scheme is basically a sequence number with other numbers and letters before and sometimes after.  It was designed by noted Naval radio engineer George H. Clark.  The actual implementation and assignments were left to A. M. Trogner, the chief draftsman of the Navy's Bureau of Steam Engineering.  Clark's scheme was called "The U.S. Navy Type Number System."

The first use had a two or three letters followed by the sequence number. The letters always started with a 'C' if the key was designed and made by a contractor. This was followed by one or two letters denoting the manufacturer of the key. The letters 'CL' denoted Fritz Lowenstein and 'CAM' denoted Manhattan Electrical Supply Co., for example. Both of these names are familiar to key and wireless collectors. See the table below for a full list of codes and makers. Most keys labeled with this scheme have little or no other identifying marks.  By 1943, the large number of contractors made it necessary to go to four letter combinations, such as 'CAQZ' for Brelco.

If the key was designed by the Navy, then the letters started with 'SE.' The 'SE' represents the Bureau of Steam Engineering, the arm of the Navy responsible for communications equipment. The Navy designed 'SE' keys were made both by the Navy and by contractors. A typical number for these keys would be 'SE-68A.' The trailing letter denotes an alteration to the contract. Most 'SE' keys are marked with the maker's name and ratings of the key. A photo of an SE-923 is shown below and to the right.  It has a label that reads, "AUXILIARY HAND SENDING KEY / 500 CYCLES / MADE FOR NAVY DEPARTMENT (BU. S.E.) / LOWENSTEIN RADIO CO. INC. BROOKLYN N.Y. / REQ. NO. NAS681 -- CONTRACT NO. 43945 -- TYPE NO. SE-923 -- DATE 1919 / KW 1/4 & 1/2 -- SER. NO. 297 -- AC VOLTS 250 -- AC AMPS 5."

Because the numbers are sequential, it is possible to estimate the date of design. The 'SE' sequence number had passed 1,400 by 1918. In the above example, 1919 is the date of manufacture. The sequential number reflects the date of design; this key was designed before 1918.  Keys could have been manufactured years later and often were. Note that the number applied to all Navy communications equipment, not just keys, so the 'SE' numbers grew large quickly.  'SE' numbering was abandoned in 1925.  The SE-923 shown in the photo was used with Navy 1/4 KW and 1/2 KW spark transmitters.

Between W.W.I and W.W.II (most likely the early 30s), the numbering scheme was not able to keep up with the exploding inventory of communications equipment, so the scheme was modified. The prefixing letters were retained to identify the contractor. However, the rapidly growing serial number gave way to a 'classification' of the equipment. There were dozens of classifications. For example, the numbers '19' denoted batteries, the number '61' insulators and the number '26' denoted 'keys - telegraph: manually operated.' Three numbers following the classification denoted the specific model. A letter following the number denoted a modification to the original contract.

Let's take apart the CTE-26003A used in the introductory example. The 'C' is the common Navy prefix. The 'TE' denotes Telephonics as the maker. The '26' denotes this is a telegraph key. The '003' is the third model in this numbering scheme. The 'A' denotes a modification to the original design.

At the start of W.W.II, the Navy and the Army adopted adopted a joint type numbering system. These numbers all start with AN, representing Army-Navy. These numbers first appeared on communications gear in December of 1942. It is not known when keys began being marked with this system. Keys numbered under the old system continued to made many years after the advent of the new system.

The two tables below show the Navy manufacturer's code and the actual manufacturer. In the first table, these codes are for makers of all types of communications gear. Those that actually made keys are a sub-set.  The second table has been abbreviated to those manufacturers known to the author that actually made telegraph and radiotelegraph keys.  There are likely more manufactures that are unknown to the author.  Refer to the complete 'C' listing by Fred Chesson in AWA Review No. 7 (shown in the bibliography).
 

Early U.S. Navy Type Number System, 1915 to c. early 1930s

CA	American Radio Research Corp.
CAB	Baldwin Telephone Co.
CAC	Central Telephone Co.
CAD	Domestic Manufacturing Engineering Co.
CAE	Cutler Hammer Manufacturing Co.
CAF	John Firth
CAG	General Radio
CAH	Cutter Manufacturing Co.
CAJ	Holtzer Manufacturing Co.
CAK	William J. Murdock
CAL	Locke Insulator Co.
CAM	Manhattan Electrical supply Co.
CAN	Sagame Electric Co.
CAO	Ward Leonard Co.
CAP	Frank B. Perry
CAQ	Robbins and Meyers
CAR	Roller Smith
CAS	Chloride of Silver Co.
CAT	American Transformer Co.
CAU	Triumph Electric Co.
CAW	C. & C. Electric Co.
CAX	Metropolitan Electric Co.
CAV	Industrial Controller Co.
CAY	West Electric Controller Co.
CB	Crocker Wheeler Co.
CD	E. J. Simon
CF	DeForest Radio Telephone & Telegraph Co.
CG	General Electric Co.
CH	Electrose Insulator Co.
CK	Kilbourne and Clark
CL	Fritz Lowenstein
CM	Marconi Wireless Telegraph Co. of America
CN	National Electric Supply Co.
CO	Copely Manufacturing Co.
CP	Cutting and Washington
CQ	International Radio Telegraph Co.
CR	Wireless Specialty Apparatus Co.
CS	Sperry Manufacturing Co.
CT	Federal Telegraph Co.
CU	Miller Resse Hutchinson
CV	Weston Instrument Co.
CW	Western Electric Co.
CY	Wireless Improvement Co.
SE	Bureau of Steam Engineering, U.S. Navy

Later U.S. Navy Type Number System, c. early 1930s to post W.W.II

CAY	Westinghouse Electric & Mfg. Co.
CABH	Signal Electronic & Mfg. Co.
CABJ	Lionel Corp.
CAKU	Winslow Co.
CAPH	Telegraph Apparatus. Co. (Ted McElroy)
CAQZ	Brelco
CAZ	Brooklyn Metal Stamping Co.
CAZT	Electro Specialty Co.
CBBX	Western Union Telegraph Co.
CDM	D. P. Mossman Co.
CEA	Bendix
CEJ	E. F. Johnson
CHD	Hardwick-Hindle, Inc.
CJB	J.H. Bunnell
CJF	J. F. Frietz
CJY	Leach Brothers
CKI	Chicago Apparatus Co.
CLR	Leach Relay
CLS	L.S. Brach
CLT	Lundquist Tool & Mfg. Co.
CMH	American Radio Hardware
CMI	Molded Insulator
CMK	McElroy Electronics (Ted McElroy)
CN	National Electric Machine Shops Inc.
COL	Collins Radio Co., Inc.
CRL	Centralab/Globe Union and Remler Co.
CRR	Bendix
CRV	RCA Victor, Div of RCA
CSE	Signal Electric
CTC	Chicago Telephone Supply
CTE	Telephonics Corp.
CUZ	United States Telev. Mfg. Co.

Bibliography

Chesson, Fred W. Navy Electronics Directory. Antique Wireless Association Review, Vol. 8, 1993

Howeth, L.S. Captain, USN. History of Commuications-Electronics in the United States Navy. Washington D.C., 1963

Old Timers Bulletin, Vol. 22. No. 3, December 1981, The Collectors Choice - The SE-1420/IP-501 Receiver. (Notes on Navy type numbering system from 40 years previous by George Clark, RCA historian)

Mote, Ray. World War Two Nomenclature Systems. 1994, (Unpublished manuscript)

Chesson, Fred W. Navy "C" codes: "Electronic Military Equipment, Naval Equipment Manufacturers". Antique Wireless Association Review, Vol. 7, 1992

Burlingame, Lynn, N7CFO Email to Neal McEwen, March 1996

For more information, visit the Telegraph Office home page

Neal McEwen, k5rw@telegraph-office.com