User's Manual

SYSTEM DESCRIPTION, INSTALLATION, AND MAINTENANCE MANUAL
ARINC 781-200 SDU and SCM
23-15-30 2-13
DATE TBD
(2) Call Priority and call Pre-emption
The A781-200 system has four priority settings for calls:
• 1 Emergency
• 2 High
•3 Low
• 4 Public
(a) Setting the Call Priority
You can set the priority for an air-to-ground 4-wire Classic call before making the
call.
This priority setting allows for preemption of existing lower priority cockpit Aero
H+ calls if insufficient satellite resources exist to establish an independent call,
and for preemption of calls and services within the cabin.
If the 4-wire Classic call is the same priority as an existing call, the established
call will be retained and the new call will be queued.
Cockpit calls over SBB are Public priority calls. You can not change the priority.
All calls made from the interfaces other than the cockpit 4-wire phones or ACARS
CMU are Public priority calls.
(b) Receiving a Priority Call
If a cockpit call is in progress and a higher priority ground-to-air call is received,
the higher priority incoming call will preempt the existing call. The preemption is
automatic, and the caller in the cockpit has no option to choose between calls.
(c) Pre-empting Calls
You can preempt an existing priority 4 cabin call with a priority 4 cockpit call.
• To preempt a call, on the SAT-PHONE 1/2 menu press the button next
to PREEMPT.
• To QUEUE a call, on the SAT-PHONE 1/2 menu press the button next
to QUEUE.
• To remove a call from the QUEUE, on the SAT-PHONE 1/2 menu press
the button next to END QUEUE.
(3) Saving Telephone Numbers in the Telephone Directory
You can save telephone numbers to the MCDU’s telephone directory to use later,
and you can dial telephone numbers from the telephone directory.
NOTE: Saving telephone numbers in the directory may be inhibited by ORT options.