PS Engineering PMA6000M-S - Manual (Page 13)

PS Engineering
PMA6000 Series Audio Selector Panel and Intercom System
Installation Manual
200-066-0006 Page 2-6 Rev. 6, March 2005
Bottom connector pin T is an unswitched and unmuted audio input. This audio is always presented to the
headphones and speaker, regardless of the audio panel audio selections. This input can be use for critical
warnings, such as radio altimeter warnings.
2.4.13 Intercom
The top connector is for the intercom function. All mic and headphone jacks must have insulating washers,
the cable must be Teflon coated, twisted-shielded wire, and the shield must only be connected to the
ground return wire only at the intercom connector. NOTE: This harness can be custom made by PS Engi-
neering, Inc. Simply call the factory and obtain a wire harness work-sheet. The harness will be made to
your specifications and fully functionally tested. All hardware is included. (See Appendix C (mono) and E
(stereo) for intercom connection configurations).
2.4.13.1 Push-to-talk intercom
PMA6000-series units with intercom board (second series of numbers on data plate) serial number above a
“G” series in stereo, or “MO series in mono, include a push-to-talk intercom capability.
In some extremely high noise environments, it may be desirable to have a push to talk (PTT) intercom,
instead of relying on voice-activation (VOX).
To operate the PTT, simply rotate the PMA6000 squelch control to maximum (fully CW). Grounding the
appropriate pin on the top connector through a momentary switch will open only that intercom channel.
The pilot and copilot are individually controlled (Top connector, pins 22 and 21, respectively). All passen-
ger mics are controlled with pin 20.
The same pins are used for both mono and stereo PMA6000 Systems.
This applies ONLY to units with applicable serial numbers. If a unit with serial number below that indi-
cated is installed in a position wired for the PTT, no damage will occur, only the ICS PTT function will not
function.
2.4.14 Digital recorder (-IRS units only)
If the PMA6000-series unit is identified with Option 1, there is an internal recorder built into the unit. This
stores the last 60 seconds of radio traffic from the selected Comm transceiver (the one selected for trans-
mit).
To use this function, a normally-open momentary switch is installed between the top connector Pin 19 and
aircraft ground. A low-current switch is recommended.
A radio signal of more than 1 VRMS is needed to trigger the IRS. Therefore, if the IRS does not seem to be
recording, increase the aircraft radio volume slightly.
2.5 Adjustments
The PMA6000 is factory adjusted to accommodate the typical requirements for most aircraft configura-
tions. There are three adjustments however, that will allow the installer to tailor the specific functions. The
numbers correspond to identification numbers stamped on some trays.