APPENDIX A
MIL-HDBK-162A
Volume 1 of 2
15 December 1965
LIST OF PREFIX LETTERS USED WITH TYPE NUMBERS (cont'd)
TS ..........................................
Handsets, including transmitter, receiver, and appropriate mounting, but not including apparatus
box, etc.
TU ..........................................
Transmitter tuning units.
VA ..........................................
Variometers.
VB ..........................................
Vibrators.
VO..........................................
VT ..........................................
Radio tubes
W ...........................................
Wire.
WC (1 to 200) .........................
Submarine cables.
WC (201 to 300) .....................
Rubber-insulated subterranean cables.
WC (301 to 400) .....................
Paper-insulated armored cables.
WC (401 to 500) .....................
Paper-insulated unarmored cables.
WC (501 to 600) .....................
Specia1 types of cables.
WC (601 to 700) .....................
Power cables.
WRS.......................................
Wire Repair Stations - Field.
WT .........................................
Weights (for antenna or other purposes).
EXPLANATION OF THE NAVY TYPE DESIGNATION SYSTEM
Navy type designations are assigned to denote major units and also to most component parts likely to require
replacement during the normal life of the equipment involved. There are two systems of type designations the Numerical
System of Navy Type Designations, and the Alphabetical System of Navy Type Designations.
The Numerical System. In the numerical system the designation is composed of a Navy type number (e.g. 21426), a
group of prefix letters to indicate the manufacturer of the item (e.g. CZZ) and when necessary, a suffix letter. The prefix
letters and the Navy type number are separated by a dash to form the complete Navy type designation (e.g. CZZ-21426).
Once prefix letters are assigned to a manufacturer the same designating letters remain the permanent identification of
the company and shall precede the Navy type numbers of all mater1Al manufactured by him. Preliminary models of
major units are identified by a spec1Al description consisting of the Navy type number assigned for the corresponding
unit of the production equipment prefixed by the letter 'X" i.e, CRV-X52041. The numerical portion of the Navy type
designation is assigned in order of receipt of request, the last three of four numbers being the order, the first two being
the "class". The significance of the first two digits in each type number is shown in the table below.
The suffix letter is assigned to differentiate units of improved or different manufacture which are entirely
interchangeable as units but, due to difference in construction, are not necessarily interchangeable with respect to their
integral parts. The suffix letter is separated from the numerical portion by a dash. For example:
1. Navy Type -61046-A insulator is identical to 61046 except the glaze is changed from white to chocolate
color.
2. Navy Type -21426-A motor-generator set is identical to -21426 except that steel has replaced cast-iron
throughout.
The Alphabetical System. The alphabetical system, which is used for units pecul1Ar to radar equipments and
special apparatus, is analogous to the numerical system except the last three or four numbers of the numerical portion
are replaced with alphabetical letters starting with AAA and progressing alphabetically; such as, AAA, AAB, AAC --- AAZ,
ABA, ABB -- etc. Also, the suffix letter is replaced by a suffix number; the first modification being indicated by the
number "1", etc. A few examples of this system are CZZ-21AAA, CRV-46ABK, CRV-66ACY, CRV-66ACY-1, etc. The
fundamental principles governing the application of both systems of Navy type designations are the same.
1A-11
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