PS Engineering PAC24 Installation Manual - Manual (Page 18)

PS Engineering
PAC24 Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-240-0010 Page 2-11 Rev. 24, Dec. 2013
2.4.12 Intercom wiring
See Appendices for intercom connection configurations. It is critical to the proper operation of this system
to have this connector wiring made in accordance with these diagrams. Use 2- and 3-conductor, MIL-spec
cable as shown. Connect the shields at the audio panel end only, and tie to the audio low inputs as shown.
2.4.12.1 Push to talk intercom
The PAC24 can be used as an IntelliVox® intercom, or, as a keyed intercom. Switching J3 pin W to
ground will inhibit the IntelliVox® and the intercom squelch will not open until the ICS PTT switch is
activated.
The following pins are used to control the intercom when PTT ICS is desired. Pin 11 must be grounded
through a momentary switch for the pilot to talk on the intercom (with W also grounded). Pin M must be
grounded through a momentary switch for the copilot to talk on the intercom (with W also grounded).
2.4.13 Entertainment Input (J3 Pin 7)
If music or entertainment is desired, a monaural input can be applied to Pin 7 of J3.
NO T E : Use t h e l ow l evel ou t p u t of a n y en t er t a i n m en t d evi ce t o con n ect t o t h e a u d i o
p a n el . Ma x i m u m si g n a l l evel i s 2 VAC p - p .
DO NO T u se a sp ea k er - l evel ou t p u t , t h i s wi l l ca u se i n t er n a l d a m a g e i n t h e a u d i o
p a n el .
All entertainment devices must be switched off for both takeoff and landing.
2.4.13.1 Entertainment distribution
The entertainment source provides music for all intercom positions. In ISO, it is removed from the pilot.
The PAC24-system incorporates a "Soft Mute" system. This will mute the entertainment devices during
ICS or radio conversation.
Any signal appearing in the unswitched audio inputs will always mute the entertainment sources, even
though the passengers may not hear the audio tone itself.
Caution: Local oscillators and internal signals from some entertainment equipment can cause undesired
interference with other aircraft systems. Before takeoff, operate the entertainment devices to determine if
there is any adverse effect within the aircraft systems. If any unusual operation is noted in flight, immedi-
ately switch off the entertainment devices.
All entertainment devices must be switched off for both takeoff and landing.
2.4.13.2 Entertainment inhibit
The music input to the PAC24 uses the existing Speaker Power input from the KMA24-71. This pin
should be removed even if music is not desired. However, if avionics power remains on Pin 7, there is the
possibility of power ripple entering the system. The Music input can be deactivated from the front panel
by pressing the NAV 1 and AUX (ADF in –0500) buttons for at least 3 seconds. The audio panel will then
ignore any signal on this input, until the Music Off mode is toggled again.
2.4.14 Intercom expansion
The PAC24 contains a five-place intercom (pilot, copilot and three passengers). The passengers are on the
same audio output as the copilot. If a true “crew” mode is desired, or in applications where more intercom
positions are needed, PS Engineering can provide intercom expansion units, such as the IntelliPAX, part
number 11606 or 11606R. These can add up to six additional stereo intercom stations, plus independent
stereo music input. Note: Observer versions (-0400 or -0401) are wired differently that others. Please
use correct wiring diagram to avoid damaging the unit.