PS Engineering PMA450 Installation Manual - Manual (Page 13)

PS Engineering
PMA450 Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-450-0000 Page 2-6 Rev. 3, November 2014
2.4.10 Public Address Mode
By holding the middle line-select pushbutton for more than one (1) seconds, the PMA450 will be placed
into public address (PA) mode. In this mode, the pilot will be talking over the cockpit speaker when he
presses his PTT switch. Copilot will still continue on the selected COM radio.
The display will include PA & SPR on the right side, and change to PUBLIC ADDRESS when the pilot’s
PTT is pressed.
2.4.10.1 PA Active Output (J2, Pin 19)
PA Active Out is a discrete output on J2 Pin 19 which will go low when PA mode is selected, providing a
logic level that can be used to incorporate a speaker-switching scheme. This 50 mA circuit (10Ω Z) can
control a switching means such as a small relay or other switching means that can transfer the speaker out-
put amplifier from the cockpit speaker to drive another cabin speaker. If the PA mode is used with a micro-
phone in proximity to an active cockpit speaker, feedback might result.
2.4.10.2 PA Mute (J2, Pin 12)
Pin 12 of J2 is a TTL logic output that is pulled low during PTT operation. This is used to control external
public address or external entertainment systems and prevent feedback during radio transmission.
2.4.11 Audio Active Output (J1, Pin 24)
Pin 24 on the J1 connector (and PA Mute Pin 12 on J2) should be connected to Apollo CNX80 for audio
message prioritization. The output is logic low when radio audio is present. Refer to CNX80 installation
manual for details.
2.5 Intercom wiring
See Appendix C and D 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.
NOTE
The intercom harness can be custom made by PS Engineering, Inc. Simply call the factory or www.ps-
engineering.com to obtain a wire harness work sheet. The harness will be made to your specifications and
fully functionally tested. Harness can be ordered with jack, or without the intercom jacks installed, for easi-
er wire routing through the aircraft.
2.5.1 Music Inputs
The PMA450 has two INDEPENDENT music inputs. Music input number 1 is J2 pins 23 (left channel)
and 24 (right channel), with respect to pin 25, and Music number 2 is connected to 26 (left channel), 27
(right channel), with respect to 28.
PMA450 has Bluetooth® connectivity to stream music from a paired device. This stream is distributed as
Music 1 and is connected in parallel with Music number 1. Refer to §
3.9 for more information.