Microair Avionics
EC2002 Altitude Encoder
16
th
April 2010
EC2002 Installation Manual 01R12.doc
Page 8 of 16
3.2
Electrical Requirements
All wiring associated with the EC2002 installation in an aircraft, should comply with FAA AC 43.13-1A
Chapter 11 or equivalent requirements. All wiring should be a minimum 22AWG in size.
Power may be supplied to the EC2002 as a switched supply from the transponder, or directly from the
aircraft bus. The EC2002 can operate with a supply voltage ranging from +10V to +33V. The maximum current
requirement for the EC2002 is 200mA (heater element full on, 24V Supply).
Where the power for the EC2002 is to be supplied from the aircraft bus, the positive line should be switched
and passed via a circuit breaker with a rating of no greater than 1 A. Both the switch and the circuit breaker
should be clearly labelled as “ALTITUDE ENCODER”. A dedicated ground line should be run from the
EC2002 to the transponder, and be grounded to the transponder’s power ground to ensure correct signal levels.
EC2002Pin
Assignment
TRANSPONDER PIN ASSIGNMETS
Microair
T2000SFL
King
KT76A
Terra
TRT250
Narco
AT-150
Garmin
GTX 320
Collins
TDR-950
1
D4
21
2
A1
9
M
5
7
3
12
3
A2
10
K
17
6
5
10
4
A4
11
J
16
8
6
7
5
B1
12
E
15
12
9
6
6
RS232 In
7
RS232 Out
5
8
V+
2
A/C V+
A/C V+
18
14
A/C V+
9
B2
13
C
2
10
11
5
10
B4
17
B
14
9
12
4
11
C1
18
D
3
14
10
8
12
C4
20
H
18
13
7
9
13
C2
19
L
4
11
4
11
14
V+
2
A/C V+
A/C V+
18
14
A/C V+
15
GND
3
A/C Gnd
A/C Gnd
5
13
A/C Gnd
Notes
1.
V+ means input voltage, either switched from the transponder or direct from the aircraft bus.
2.
A/C V+ means aircraft supply voltage – positive.
3.
A/C Gnd means aircraft ground – negative.
4.
Where the power is not supplied directly from the transponder, it is recommended that an indicator
light be installed to show when power is being supplied to the encoder.
