User's Guide

DRAFT
Page 1-10
17 Mar 2016
23-15-87
© Honeywell International Inc. Do not copy without express permission of Honeywell.
SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
ARINC 781-500 SDU and SCM
• To reset the unit, press and hold the Test button for at least 5 seconds.
• To initiate self-test (when no LEDs are flashing), momentarily press the Test button.
• When the self test completes (power on or user initiated) the Power LED will illuminate steady
for a period of 60 seconds and then it will deactivate for the duration of operation.
NOTE: During initial power-up or self-test execution, a momentary press of the self-test
button is ignored.
The LEDs indicate the results of the self-test. Table 1-5 provides information about the meaning of
LED signals.
6. Software Description
All operating software meets RTCA/DO-178B Level D requirements.
The SCM does not contain any software. Only configuration parameters are stored in the SCM.
The SDU software is not partitioned. The software is modular and modules run on individual Software
Logical Units (SLUs) within the SDU:
• Each channel card has a single SLU.
• Control and Data Processor card has a Control SLU and a Data SLU.
• Voice card has a Voice SLU.
DRAFT as of
4 Mar 2016