PS Engineering
PMA8000-SR Series Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-880-0000 Page 2-5 Rev. 13, July 2006
lighting system to work. The photocell mounted in the unit face will automatically adjust the intensity of
the push-button annunciation LEDs.
2.4.10 Unswitched inputs
J1, pins 31, 29 and J2 pin 15 are unswitched, unmuted inputs # 1, 3 and 4, respectively. These inputs are
presented to the pilot and copilot regardless of the audio configuration, and will always mute the enter-
tainment inputs. These 510Ω inputs can be used for altimeter DH audio, GPS waypoint audio, autopilot
disconnect tones, or any other critical audio signal. Unswitched #1 is always presented to the speaker.
Unswitched #2, J1 pin 44 is unswitched, but muted (controlled by the speaker switch), and suitable for air-
to-ground (Flitefone) telephone ringer This input is not related to the cellular telephone interface.
Unswitched 3 and 4 inputs are always presented to the crew headphones and to the aircraft speaker.
NOTE: These inputs are fixed (1:1), and any audio level adjustments must be made at the input source.
Unswitched Input 1 is presented to the pilot in Fail-Safe (power off) condition.
2.4.11 Public Address Mode
Although equipped with a PA mode, the PMA8000-SR is shipped from the factory with this function in-
hibited, because only a very few customers will use it. It must be initialized before use. The Sirius Radio
remote 050-803-0200, MUST be used to initialize the PA Mode. On the remote, press 3 0 0. You will hear a
beep with each key press, followed by the three-beep acknowledgement.
By pressing the Mute and SPR pushbuttons at the same time, the PMA8000-SR will be placed into public
address (PA) mode. In this mode, both Com 1 and Com 2 receive indicators will blink, alerting the pilot
that when he presses his PTT switch he will be talking over the cockpit speaker. Copilot will still continue
on the selected COM radio.
When in the PA mode, J2 Pin 19 will go low, providing a digital logic level that can be used to incorporate
a speaker-switching scheme. This can control some switching means such as a relay (coil current of 100
mA maximum) that would transfer the speaker output amplifier from the cockpit speaker to drive another
cabin speaker. If the PA mode is used with a microphone in proximity to an active cockpit speaker, feed-
back might result.
NOTE: An internal configuration jumper can be removed if Pin 19 conflicts with prior installation. This
jumper is adjacent to those described in section 2.4.16.4.
2.4.12 PA Mute (J2, Pin 12)
Pin 12 of J2 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.
2.4.13 Miscellaneous Logic Output (J2, Pin 18)
Pin 18 of the J2 connector is pulled to ground whenever the AUX button is depressed. This serves as a
control line for external devices, such as an entertainment system that the pilot wishes to control.
This pin can also be used to control passenger Karaoke Mode, by connecting to pin 13 of the J2, or as a PA
cockpit/cabin speaker relay control, as long as the maximum current does not exceed 100 mA..
NOTE: J2, Pin 18 should NOT be used as a logic switch for music muting if the AUX is going to be used
to switch DME or auxiliary audio.
2.4.14 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.