User's Manual

SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
ARINC 781-200 SDU and SCM
23-15-30 1-9
DATE TBD
D. POTS
The SDU supports two POTS interfaces.
E. CEPT-E1
The SDU supports one CEPT-E1 interface.
F. ISDN
Two ISDN interfaces are currently not supported.
G. Maintenance Port
The SDU is equipped with a maintenance port,
located on its front panel. The
maintenance port provides the physical connection to a password-protected
Maintenance Port Utility (MPU) that provides a system interface for users or service
personnel who need to monitor or troubleshoot the system.
For more information on configuring the maintenance port, refer to "Connecting to the
MPU" on page 4-2.
H. LEDs
The front panel of the SDU has two LEDs to indicate unit status:
• One green LED labelled Power
• One red LED labelled Fa
ult
Table 1-5 provides information about the LED signals.
Table 1-5 SDU LED Status
Power LED Status Fault LED Status Description of SDU Status
LED is on LED is off No fault detected
LED is on LED is steadily on as long as
the fault
exists
LRU fault detected
LED is on Flashing at 1 Hz with a 50%
duty
cycle while the fault
exists
System fault detected but not isolated
to the LRU
Alternating flashing of Po
wer and Fault LEDs Self-test in progress
I. Self-Test Button
The front panel of the SDU has a recessed button labelled Te
st:
• To reset the unit, press and hold the Test button for at least 5 seconds
• To initiate self-test (when no LEDs are fla
shing), momentarily press the Test button
• When the self test completes (power on or us
er initiated) the Power LED will illuminate
steady for a period of 60 seconds and then it will deactivate for the duration of
operation.