PS Engineering PMA7000CD Installation Manual - Manual (Page 14)

PS Engineering
PMA7000CD- Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-790-0010 Page 2-6 Revision 10, September 2005
2.5.9 "Swap" Mode
When a momentary, normally open, push-button switch is connected between pin 10 on the top connector
and aircraft ground, the user can switch between Com 1 and 2 by depressing this switch without having to
turn the mic selector switch. This yoke-mounted switch eliminates the need to remove your hands from the
yoke to change transceivers. The transfer of TX indication from Com 1 to Com 2 shows that the swap has
been initiated, there is no dedicated swap indicator.
2.5.10 Backlighting
The PMA7000CD has an automatic dimming of the pushbutton annunciator LEDs and marker lamps con-
trolled by a photocell. Control of the unit backlighting is through the aircraft avionics dimmer. Connect the
dimmer control line to J1 pin D for 14-volt systems, and to J1 pin F for 28-volt systems. Pin E is light
ground.
If an external dimmer control is not used, a constant low-level back light illumination can be established
for nighttime viewing. Pin D or F (depending on system voltage) must be tied to power (J1, pin 20) for the
back lighting system to work. The photocell mounted in the unit face will automatically adjust the intensity
of the push-button annunciator LEDs.
2.5.11 Unswitched inputs
Bottom Connector, J1, pin T, pin 17, pin U and pin X are the unswitched inputs. These inputs are presented
to the pilot and copilot regardless of the audio configuration, and will always mute the entertainment in-
puts. These 510Ω inputs can be used for altimeter DH audio, GPS waypoint audio, autopilot disconnect
tones, air-to-ground (Flitefone) telephone ringer or any other critical audio signal. This input is not related
to the cellular telephone interface.
2.5.12 PA Mute (J1, Pin 18)
Pin 18 of J1 is a TTL logic output that is pulled low during PTT operation. This serves as an input to exter-
nal public address system to prevent feedback during transmissions.
2.5.13 Public Address Function (J2, Pin 18)
By connecting the top connector (J2), Pin 18 to ground, the pilot’s microphone audio is placed on the cabin
speaker output. When the pilot’s PTT is activated, his voice is heard over the speaker. The copilot can con-
tinue to use the selected com.
We recommend installing a toggle switch to connect the cabin speaker output (pin W, bottom connector) to
a rear or public address speaker instead of the cockpit speaker close to the pilot. This will prevent feed-
back.
2.5.14 Control Output (J2, Pin A)
Pin A of the top connector is pulled to ground whenever the AUX button is activated (LED on). This
serves as a control line for external devices, such as a entertainment system that the pilot wishes to control.
This could be used in conjunction with a PA to control J2, Pin 18, as well as an external relay to change to
the cabin speaker from the cockpit.
This pin can also be used to control passenger Karaoke Mode, by connecting to pin V of the J2, or as a
copilot hook switch Pin L of J2, or passenger hook switch pin M, J2.
2.5.15 Intercom wiring
The top connector (J2) is for the intercom, CD interface and additional functions. See Appendix for inter-
com 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. Con-
nect the shields at the audio panel end only, and tie to the audio low inputs as shown.
NOTE: The top connector harness can be custom made by PS Engineering, Inc. Simply call the factory
and obtain a wire harness work-sheet. The harness will be made to your specifications and fully function-
ally tested. All hardware is included.