Revision A
T-48 90 008 026
1-5
1.7
Abbreviations, Acronyms and Glossary of Terms
A/A Air
to
Air
A/A B
Air to Air Beacon
ac or AC
Alternating Current
A/D Analog
to
Digital
Address
The unique code to which a MODE S transponder replies. This is not to
be confused with the 4096 code used for identifying ATCRBS
transponders. The address of a MODE S transponder is not alterable by
the pilot or crew.
Altitude
The pressure altitude of the aircraft as transmitted by an ATCRBS or
MODE S transponder. This information is obtained from an external
sensor and transmitted to the transponder.
AM Amplitude
Modulation
ATCRBS
Air Traffic Control Radar Beacon System
ATC
Air Traffic Control
AUT Aircraft
Under
Test
BIT
Built in Test
Comm
Refers to the communications and data-link capability of a MODE S
transponder. There are four (4) capabilities: No Comm, Comm A/B,
Comm A/B/C and Comm A/B/C/D. The Comm. capability is displayed
when the transponder is determined to be a MODE S.
CW Continuous
Wave
D/A Digital
to
Analog
dB Decibel
dBm
Decibels above 1 milliwatt
dc or DC
Direct Current
DME
Distance Measuring Equipment
DPSK
Differential Phase Shift Keying. The method of modulation used for the
selective MODE S uplink interrogations.
DF
Downlink Format. The format included in a MODE S transponder reply
to an interrogation or squitter message that indicates the type of message.
ELM
Extended Length Messages
FAA
Federal Aviation Administration
FAR
Federal Aviation Regulation
FIFO
First In First Out
FREQ Frequency
ft. Feet
G/A Ground
to
Air
Hz Hertz
IF Intermediate
Frequency
IFF
Identify Friend or Foe
KHz Kilohertz
kts. Knots
LCD Liquid
Crystal
Display
LED
Light Emitting Diode
MODE S
A secondary radar system where transponders can be individually
interrogated or selected (the “S” in MODE S) so that in a crowded air
traffic area, the amount of interference or garble can be reduced to a
minimum.
ATCRBS/MODE S All Call
Interrogation that causes all ATCRBS/MODE S transponders to reply.
MHz Megahertz
nmi. Nautical
mile
