Set Indicator Letter
1st Letter
2nd Letter
3rd Letter
Installation Class
Type of Equipment
Purpose
V
Vehicular (ground)
N
Sound in air
S
Detecting/range
and bearing,
search
W
Water surface and
P
RADAR
T
Transmitting
underwater combined
Z
Piloted-Pilotless
Q
Sonar and underwater sound
W Automatic flight
airborne vehicles
or remote control
combined
R
Radio
X
Identification and
recognition
S
Special or combination
Y
Surveillance
(search, detect,
and multiple
target tracking)
and control
T
Telephone (wire)
Z
Secure (NSA
use only)
V
Visual and visible light
W Armament (peculiar to
armament not otherwise
covered)
X
Facsimile or television
Y
Data processing or computer
Z
Communications (NSA use
only)
Table 5-1 -- Set indicator letters
ATC COMMUNICATIONS AND COORDINATION EQUIPMENT
Some ATC equipment is used in both the control tower and the RADAR room.
Controllers must become familiar with this equipment and its function in each ATC
branch.
5-3
