Altitude Gray Code - Garmin GPS 400W Installation Manual

4.3 A ltitude Gray Code
4 1 B
Altitude input is useful for advisory vertical navigation (VNAV) calculations.
Pin Name
ALTITUDE D4
ALTITUDE A1
ALTITUDE A2
ALTITUDE A4
ALTITUDE B1
ALTITUDE B2
ALTITUDE B4
ALTITUDE C1
ALTITUDE C2
ALTITUDE C4
ALTITUDE COMMON
These inputs are considered active if either the voltage to ground is <1.9 V or the resistance to ground
is <375 . These inputs are considered inactive if the voltage to ground is 11-33 VDC.
Some transponders and other altitude encoder receivers do not have internal isolation
diodes to prevent the unit from pulling the encoder lines to ground when the unit is off.
These units require a diode added to the installation harness for each encoder line. The
anode should be connected on the receiving unit's side and the cathode should be
connected on the encoder side. A set of diodes is required for each unit without internal
diodes. The 400W Series unit includes internal diodes for isolation of the encoder lines.
Refer to Section 5 .3.9 for the gray code altitude checkout.
3 8 4 H
Refer to F igure H-6 for the gray code altitude interconnect.
3 8 5 H
Page 4-6
Rev. F
Connector
P4001
P4001
P4001
P4001
P4001
P4001
P4001
P4001
P4001
P4001
P4001
NOTE
Pin I/O
70 In
69 In
68 In
67 In
66 In
65 In
64 In
63 In
62 In
61 In
60 In
400W Series Installation Manual
190-00356-02