TM 55-1520-228-BD
ELECTRICAL AND AVIONICS SYSTEM
Table 11-2. Function and Designation Letters (Cont)
CIRCUIT
CIRCUIT
DESIGNATION
DESIGNATION
LETTER
CIRCUITS
LETTER
CIRCUITS
S
RADAR:
SA-Altimeter
SF-Intercept
SG-Gunlaying
SM-Mapping
SN-Navigation
SQ-Bombing
SR-Recorder
SS-Search
SV-Special systems
SW-Warning
SX-Recognition (IFF)
T
SPECIAL ELECTRONIC:
TA-Adapter
TB-Radar control
TC-Radio control
TD-Airborne announcing
TE-Electronic countermeasure
TF-Repeat back
TG-GM homing
TH-Infrared
TK-Telemetering
TL-Attitude indicator
TM-Chaff dispenser
TN-Navigation
TP-Beacon (crash and locator)
TQ-Transmitters and receivers
TR-Receivers
TT-Transmitters
TU-Reconnaissance
TW-Weather devices
TZ-Bombing devices
U
MISCELLANEOUS ELECTRONIC:
Electronic wiring for which no
"R", "S", or "T" designation has
been assigned by the procuring
activity shall have the circuit
function letter "U" assigned.
Examples of wiring for which
the circuit function letter "U"
will be assigned are common leads
to electronic equipments and
systems interconnection wiring
such as antenna or power circuits
common to more than one equipment
or system.
V
DC POWER and DC control cables
for AC systems shall be identi-
fied by the circuit function
letter "V."
W
WARNING AND EMERGENCY
Enclosure release and
locks
Fire extinguishers
Flare release
Fire detector
Intercrew buzzer or light
X
AC POWER:
Wiring in the AC power system
shall be identified by the
circuit function letter "X."
Y
ARMAMENT SPECIAL SYSTEMS:
Y*A-Air to air
Y*B-Air to surface
Y*C-Multimode
Y*M-Missile-guidance
Y*T-Turret
*
Armament special
system number
Z
UNASSIGNED
11-5
To Next Page
