Pa Function; 3.1.10 Auxiliary Entertainment Inputs; Intercom System (Ics) - Garmin GMA 340 Installation Manual

3.1.9

PA Function

The PA mode is activated by pressing the PA button (11). Then, when either the pilot's or copilot's microphone
is keyed, the corresponding mic audio is heard over the cabin speaker. If the SPKR button (12) is also active,
then any selected speaker audio is muted while the microphone is keyed. The SPKR button does not have to be
previously active in order to use the PA function. Pilot and copilot PA microphone speaker levels are adjustable
through an access hole in the top of the unit (see figure 2-3).

3.1.10 Auxiliary Entertainment Inputs

The GMA 340 and 340H provide two stereo entertainment inputs: MUSIC 1 and MUSIC 2. The 340 Dual ADF
has only MUSIC 1. MUSIC 1 is soft-muted during all aircraft radio activity and normally during ICS activity.
MUSIC 2 is a non-muted input. These inputs are compatible with popular portable entertainment devices such as
cassette tape or CD players. The headphone outputs of these devices are used and plugged into MUSIC 1 or
MUSIC 2. Two 3.5 mm stereo phone jacks should be installed in a convenient location for this purpose.
MUSIC 1 and MUSIC 2 have characteristics that are affected by the active intercom mode (see paragraph 3.1.11).
Refer to the notes in paragraphs 2.6.2 and 2.6.6 for mono/stereo connections and music amplification.
3.1.11 Intercom System (ICS) (Pilot and Copilot functions are reversed on the 340H)
Intercom volume and squelch (VOX) are adjusted using the following front panel knobs (note that knobs are
reversed in the 340H version:
• LEFT SMALL KNOB  Unit on/off power control and Pilot ICS volume (5). Full CCW DETENT
• LEFT LARGE KNOB  Pilot ICS mic VOX squelch level (6). CW rotation increases the amount of
• RIGHT SMALL KNOB  IN position: Copilot ICS volume. OUT position: Passenger ICS volume
• RIGHT LARGE KNOB  Copilot and passenger mic VOX squelch level (8). CW rotation increases
Each microphone input (six total) has a dedicated VOX circuit to ensure that only the active microphone(s) is/are
heard when squelch is broken. This represents a vast improvement over single-gate systems and reduces the
amount of background noise in the headphones during cockpit communications. After the operator has stopped
talking, the intercom channel remains momentarily open to avoid closure between words or normal pauses.
The GMA 340 provides three intercom modes: PILOT, CREW and ALL. The mode selection is accomplished
using the PILOT (10) and CREW (9) buttons.
Pressing a button activates the corresponding ICS mode. Pressing again deactivates the mode. The operator can
switch directly from PILOT to CREW or from CREW to PILOT by pressing the other mode button. ALL mode
is active when neither PILOT or CREW mode is selected. These modes allow different degrees of interaction
between the crew and passengers:
Page 3-4
Rev. L
position is OFF.
mic audio (VOX level) required to break squelch. Full CCW is the "hot
mic" position.
(7).
the amount of mic audio (VOX level) required to break squelch. Fully
CCW is the "hot mic" position.
GMA 340 Installation Manual
190-00149-01