User's Guide

DRAFT
Page 3-7
17 Mar 2016
23-15-87
SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
ARINC 781-500 SDU and SCM
© Honeywell International Inc. Do not copy without express permission of Honeywell.
5. Owners Requirements Table (ORT)
A. ORT Overview
The A781-500 system includes a secure and user ORT. Secure ORT files must be certified for the
aircraft type on which the equipment is installed. Items in user ORT files can be modified by
individual customers and may be customized to an individual aircraft.
You can change secure ORT parameters only by uploading an ORT file. To obtain a secure ORT
file, contact RC Product Support.
The ORT file is loaded on to the SCM using an ARINC 615A data loader. You can only load ORT
data when the aircraft is on the ground and the data load discrete is asserted. When the SDU boots,
it compares the ORT file in its memory to that in the SCM. If the ORT files do not match, the SDU
loads the file from the SCM into its memory.
Some user ORT parameters can be modified in the SDU ORT. You can reset the SDU ORT to the
default values stored in the SCM in the maintenance menus.
To modify the user ORT parameters, use the ORT Application. To obtain the ORT Application,
contact RC Product Support.
For more information see the following guides:
• Publication No. D201511000062, A781-500 User ORT User Guide
• Publication No. D201511000064, A781-500 Secure ORT User Guide
• Publication No. D201511000061, A781-500 ORT Application Install Manual.
6. Passive Intermodulation (PIM) Test
This section describes the passive intermodulation test. You must execute the PIM test after installation
if the A781-500 SDU operates in SBB mode.
A. Overview
To meet Inmarsat requirements for SBB operation, the A781-500 SDU can test for passive
intermodulation effects. The PIM test verifies that the transmit signal from the A781-500 SDU does
not degrade or interfere with the receive signals as a result of PIM.
A781-500 SDU can only perform the PIM test when the aircraft is on the ground.
When the A781-500 SDU logs on to the SBB network, the network assigns the terminal two
channels for PIM testing. These channels are not used by other terminals so that the A781-500
SDU can transmit the test frequencies without interfering with other satellite communication
equipment or the Inmarsat satellite.
B. PIM Requirements
In order to successfully perform the PIM test, the aircraft and the satellite communication system
must meet the following requirements:
• The A781-500 SDU must have successfully logged on to a satellite that is visible at the test
location within the last 168 hours (7 days).
DRAFT as of
4 Mar 2016