PS Engineering PMA4000 Installation Manual - Manual (Page 9)

PS Engineering
PMA4000 Series Audio Selector Panel and Intercom System
Installation Manual
200-041-0002 Page 2-3 Rev 5, March 2007
2.4.2 Entertainment Input
A single entertainment device (CD player, cassette player, etc.) can be connected to the
unit. Install a 1/8-inch stereo jack in a convenient location so that the pilot can plug in the
entertainment device into the system.
For a stereo input, we recommend tying the left and right channels (tip and ring) together,
so both stereo channels are provided to the monaural audio panel, and the audio ampli-
tude available to the audio panel is increased. Audio signal at the entertainment input
must be a minimum of 1V P-P for optimum music performance. We have noticed that the
portable devices using 4 batteries seem to work better than the 2-cell types. Also we have
found that some cigarette-lighter adapters introduce noise into the system due to the volt-
age switching power supply.
2.4.2.1 Soft Mute
The PMA4000-system incorporates a "Soft Mute" system. This will mute the entertain-
ment devices during ICS or radio traffic. The entertainment input (P2, pin 25 and 13) is
heard by everyone (except by the pilot in ISO mode).
NOTE: The Soft Mute Enable switch is connected between P2, Pin
5 and ground. When this pin is grounded, the soft mute is inactive,
and the PMA4000 is in “Karoake” Mode.
Local oscillators and internal signals from some entertainment equipment can cause un-
desired 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 un-
usual operation is noted in flight, immediately switch off the entertainment devices.
NOTE: Use the low-level output of any entertainment device to
connect to the audio panel. Maximum signal level is 3 VAC p-p.
DO NOT use a speaker-level output, this will cause internal dam-
age in the audio panel.
To use a speaker level, install an AudioLink adapter (part number
101PL2), available from Crutchfield at 1-800-955-3000
2.4.3 Radio Push-to-Talk
An important part of the installation is the PTT (Push-To-Talk) switches that allow the
use of your aircraft communications radio for transmissions. There are three typical con-
figurations that can be used. Select the case that best fits the installation. Only the person
who presses their PTT switch will be heard over the radio. If the pilot and copilot both
use the PTT, the copilot position has access to the radio. The pilot position will have PTT
control regardless of the copilot when the PMA4000 is in the F
AIL
-
SAFE
mode.
CASE I: PTT is built into both pilot and copilot yokes.