PS Engineering PMA8000B Installation Manual - Manual (Page 13)

PS Engineering
PMA8000B Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-890-0101 Page 2-6 Rev. 4, April 2012
NOTE
Inputs 1, 2 and 4 are fixed (1:1), and any audio level adjustments must be made at the input source.
Unswitched #3 has a variable adjustment control located on the bottom side of the unit. This control al-
lows you to adjust the volume level of that unswitched input. Refer to Adjustments section.
The front panel jack can be configured to act as a fifth unswitched input. When configured through the
front panel function switches (see operational section), the audio input to this jack will be presented to the
pilot and copilot headsets, and not muted.
NOTE
The front-mounted utility jack is intended for portable equipment that is advisory in nature. It is NOT
INTENDED for use as a primary warning channel. Audio of importance MUST ALWAYS be hard-wired
into the unswitched inputs of the audio panel.
2.4.11 Public Address Mode
By pressing the Mute and SPR pushbuttons at the same time, the PMA8000B 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.
To enable the PA Discrete Output located at the rear connector, the internal configuration jumper, J4,
MUST be placed across both pins in the header. This jumper is shipped as open from the factory.
When this Discrete Output is enabled, J2 Pin 19 will go low when in PA mode, 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 relay 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 cock-
pit speaker, feedback might result.
2.4.11.1 Public Address Jumper
1. Remove qty. 5 Phillip head screws from the PM8000B. NOTE: THE SCREW IN THE REAR
OF THE PANEL IS A DIFFERENT LENGTH THAN THE OTHER FOUR. YOU MUST
PUT THE SHORTER LENGTH SCREW BACK IN THE SAME LOCATION OR
DAMAGE WILL OCCUR. See Figure #1.
Figure 2-2 Screw Locations
Long shaft screws
Short shaft screws