PS Engineering PAC24 Installation Manual - Manual (Page 26)

PS Engineering
PAC24 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-240-0010 Page 3-2 Rev. 24, Dec. 2013
3.3.2 Dual Panel Fail Safe Operation
In a dual installation, the PAC24 designated as Pilot’s at installation, will default to Com 1. The audio
panel designated as copilot will not operate in the off position. This prevents compromising the pilot’s
audio capability in the event of a dual audio panel problem.
3.4 Communications Selection (2)
There are 10 pushbuttons associated with the communications transceivers. The lower buttons control
which transceiver is selected for transmit.
The PAC24 gives priority to the pilot’s PTT. If the copilot it transmitting, and the pilot presses his PTT,
the pilot’s microphone will be heard over the selected com transmitter.
The PAC24 has an automatic selector mode. Audio from the transceiver selected by the Xmit button is
automatically heard in the headsets and speaker (if selected). You can check this function by switching
from C
OM 1 to C OM 2 and watch the selected audio light on the selector change from COM 1 to COM 2.
This ensures the pilot will always hear the audio from the transceiver he is transmitting on.
When switching from C OM 1 to C OM 2, while C OM 2 audio had been selected, Com 1 audio will continue
to be heard. This eliminates the pilot having to switch Com 1 audio back on, if desired.
When switching from C OM 1 to C OM 2 while Com 2 has NOT been selected, Com 1 audio will be
switched off. In essence, switching the mic selector will not effect the selection of Com receiver audio.
This is true of all transmitter selections.
3.4.1 Telephone Operation
In a single installation, the intercom mode select switch determines who is on the phone:
ISO - pilot
CREW - pilot and copilot (passengers if IntelliPAX expansion NOT present)
ALL - pilot, copilot, passengers
In a standard dual installation, the pilot and copilot can select TEL mode independent of each other by
pressing their respective COM5 XMT button. The passengers are on the phone only when the pilot has
selected TEL (Com 5) mode and his switch is in the ALL position. The copilot cannot put the passengers
on the phone, and the passengers can only get on the phone when the pilot is on the phone. In an observer
dual installation, the crew box works like a single installation.
The observer is treated like a passenger, so he would be on the phone line when COM5 XMT is selected
and the intercom switch is in ALL mode. The observer cannot select telephone mode independently.
NOTE: Selecting the COM 5 –TEL– mode will disable pilot and copilot intercom, as the intercom circuit
is transferred to the telephone use. However, sidetone will be present.
3.4.2 Stuck Microphone Protection
The PAC24 has a function designed to prevent unintentional radio transmissions and blocked frequencies.
After 35 seconds of continuous PTT on any input, the PTT line is lifted, and will remain unkeyed until the
PTT input is recycled.
3.4.3 Swap Mode (Remote transfer of com transceivers)
With a yoke mounted, normally open, momentary switch, the pilot can change from the current Com
transceiver another by depressing this switch. Activating the swap switch will select the next transceiver,
cycling from 1 to 2 to 3 etc.
3.4.4 Observer transmit selection (part number –0400 series).
If the installation uses a dual panel, observer configuration, the crew panel serves the pilot and copilot,
while the second audio panel serves the observer.