Specifications

SECTION III
INSTRUMENTATION AND AVIONICS
MODEL 560
An ID/VOICE selector is located on the right center of the audio panel. It is not a latching switch, but is
active whenever NAV 1 or 2 and/or ADF 1 or 2 (if installed) is selected. If BOTH is selected, both ID and
voice will be heard; if ID is selected, voice signals will be filtered out and coded identification signals will be
heard. If VOICE is selected, coded signals will be filtered out and voice will be heard.
The DME 2 latching switch/volume control controls the volume of DME 2 identification signals in dual
DME installations.
The marker mute and marker aural on/off/volume control are located on the bottom row of switches on
the panel. The marker mute is used to temporarily silence the marker beacon audio. Momentarily pressing
the MUTE button will mute the beacon signal as long as it remains above a minimum threshold level. When
it drops below that level, a time-out sequence will begin, which will mute it for a fixed period of time. The
MKR button may be pressed in to disable the aural signal. When the button is out (pressed again) the
marker beacon volume can be controlled with the knob, however, maximum counter-clockwise rotation will
not totally turn down the volume since a minimum signal is automatically retained in order not to miss the
aural marker signal if it has been selected on.
AUDIO CONTROL PANEL (Optional)
Two audio control panels are installed to provide individual audio selection by each pilot.
Three-position switches (SPKR-OFF-HDPH) enable all audio inputs to be selected to the speakers or
headphones. A two-position IDENT/VOICE switch is used in conjunction with the NAV and ADF switches to
monitor either voice or coded identifiers. Two concentric MASTER VOLUME knobs control the headset or
speaker volume of all selected audio sources. A PASS SPKR VOLUME knob controls the output volume of
the passenger compartment speaker.
A rotary microphone selector switch has four standard positions. COMM 1 or COMM 2 connects the
microphone in use to the respective VHF transmitter. PASS SPKR allows for announcements to
passengers through the cabin speakers. EMER/COMM 1 position may be used to operate COMM 1 radio
directly, bypassing the audio amplifier, but requires the use of a headset, and volume control is available
only at the radio. Transmitting remains normal from all microphone sources. An optional audio control
panel has a fifth position to be used for the HF system, if installed.
NOTE
• When PASS SPKR is selected, the same side cockpit speaker is muted while the
opposite speaker continues to provide normal audio reception. If both audio control
switches are selected to PASS SPKR, both cockpit speakers will be muted. The
use of PASS SPKR mode should be limited to required passenger briefings or
emergencies.
Figure 3-11. Audio Control Panel (Typical)
I 3-24 Configuration AA 56OMB-01