except for RS232 channel 2. This channel is only tested at power on and the results displayed on this page. Therefore the unit must be turned off and the receiver/ transmitter connected or disconnected and then turn the unit on to perform the test.

To test the channels:

RS232 channel 1: Connect RS232 channel 1 receiver and transmitter

RS232 channel 2: Connect RS232 channel 2 receiver and transmitter

RS422:Connect RS232 channel 1 to RS422 LOW (pin 27) and ground RS422 HI (pin 11)

ARINC 429:Connect ARINC 429 receiver and transmitter

4.3.6 ALTITUDE INPUT TEST

Select the Gray Code Altitude Test Page if this input is used. Verify that the altitude input is reading the correct altitude. NOTE: This does not display serial altitude.

4.3.7 OBI TEST

Select the OBI Test Page. Using the controls on the GNC 300 front panel, make the selections indicated below and verify the interfaces as appropriate:

OBI Data

 

VALID

Ensure that the OBI indicates the proper value

INVALID

Ensure the OBI is invalid

OBI Value

Ensure that the OBI displays the value entered when

 

the VALID option is selected

NOTE: The 3 lines that make up the OBI interface may be toggled individually. This may be done from the “Value” field. Cycle this field to the desired line (either CLOCK, DATA or SYNC) and toggle the output to HIGH or LOW.

4.3.8 SIGNAL ACQUISITION TEST

The Self Test Page will be displayed followed by the Data Base Page. Upon approval of the Data Base Page, the Satellite Status Page will be displayed. If unable to acquire satellites, relocate the aircraft away from obstructions which might be shading reception. If the situation does not improve, check the antenna installation.

Once GPS position information is available, use the DIRECT-TO key to activate the navigation function to a nearby NAVAID, intersection, or airport. Ensure any connected equipment is transmitting data to and/or is receiving data from the GNC 300 and is functioning properly (see the Pilot's Guide for more information on the DIRECT-TO function).

Av. Kit Install. Manual

190-00067-02 Rev. J

Page 24