Stamped Out - Telecommunications Security (TSEC) Nomenclature

The Nomenclature System

Telecommunications Security (TSEC) Nomenclature
Most cryptographic and COMSEC equipment used by the US military and civilian intelligence agencies is designated in the Telecommunications Security (TSEC) nomenclature. The nomenclature for equipment systems, items and assemblies (i.e. components) is slightly different.

Examples for Items and Systems: TSEC / K Y - 57

TSEC / K G - 84 C

TSEC / H N - 74

TSEC / C Y - 104 A

TSEC / C I - 10

Examples for Assemblies: K Y X - 15 A / TSEC

H G F - 96 / TSEC

(1) (2) (3) (4) (5)

Designators for items and systems are always prefixed by "TSEC/", while designations for assemblies use a "/TSEC" suffix. However, assembly designations are sometimes incorrectly quoted with a "TSEC/" prefix.

Letter (1) is the function of the equipment:

C - COMSEC Equipment System
G - General Purpose
K - Cryptographic
H - Crypto-Ancillary
M - Manufacturing
N - Noncryptographic
S - Special Purpose

Letter (2) is the type or purpose of the equipment:

G - Key Generation
I - Data Transmission
L - Literal Conversion
N - Signal Conversion
O - Multipurpose
P - Materials Production
S - Special Purpose
T - Testing, Checking
U - Television
W - Teletypewriter
X - Facsimile
Y - Speech

Letter (3) is only used for designations of assemblies and designates the type or purpose of the assembly:

A - Advancing
B - Base or Cabinet
C - Combining
D - Drawer or Panel
E - Strip or Chassis
F - Frame or Rack
G - Key Generator
H - Keyboard
I - Translator or Reader
J - Speech Processing
K - Keying, Permuting
L - Repeater
M - Memory or Storage
O - Observation
P - Power Supply or Converter
R - Receiver
S - Synchronizing
T - Transmitter
U - Printer
V - Removable Communication Security Component
W - Logic Programmer/Programming
X - Special Purpose

(4) is a model number. Each letter combination uses its own sequentially assigned model number series.

The optional suffix letter (5) denotes a specific version of the equipment. The first version uses no suffix, the first modifcation uses "A", etc.

Examples for Items and Systems:	TSEC /	K	Y		-	57
	TSEC /	K	G		-	84	C
	TSEC /	H	N		-	74
	TSEC /	C	Y		-	104	A
	TSEC /	C	I		-	10
Examples for Assemblies:		K	Y	X	-	15	A	/ TSEC
		H	G	F	-	96		/ TSEC
		(1)	(2)	(3)		(4)	(5)

The Nomenclature System

Odds N Ends