Northern Airborne Technology 3110 - Manual (Page 59)

SM3110 Rev. 4.00 3110-100 Audio Control Panel Manual
When power is restored to the unit, it will return to the last known transmit select
configuration and annunciator status.
3.3.12
Service Interphones
The 3110-100 has three interfaces for service interphone communications. Each
service interphone interface consists of a service microphone input, a headphone
output, and service keyline for communicating on the service interphone only. They are
not radio transmit capable. All three service headphone interfaces are driven from a
single amplifier.
Transmission from the pilot boom/mask mic to the Service (CAB) interphone can be enabled
using the CAB interphone transmit select button on the front panel of the 3110 ACP.
3.3.13
Passenger Address
The 3110-100 has a passenger address analog interface which is active whenever PA
is selected for transmit, and the radio PTT or hand mic PTT is keyed. This interface
also provides an output that can mute an externally connected stereo system.
PA audio signals are sent to the PA audio output and to the service headphone outputs.
3.3.14
PTT
When radio or hand mic PTT is activated, the applicable mic audio will be routed to the
selected transmitter, and all receiver and cockpit interphone audio to the pilot’s
headphone and the cockpit speaker will mute, and VOX will be disabled.
Note: PTT activity will not mute aural warnings or sidetone.
3.4 External Control Functions
The design of the 3110-100 allows for connection to various external switches,
annunciators, recorders, and warning generators. If connected, these external components
affect the operation of the 3110-100 as described in the relevant sections below.
3.4.1
Emergency Mode Switch and Annunciator
An external Emergency Mode switch may be connected to the 3110 ACP. The 3110-
100 can be linked to an external indicator lamp to display emergency mode status.
In emergency mode, one transceiver and one aural warning source may be connected
for use. The transceiver is connected to the boom/mask mic audio, radio PTT keyline
and pilot headphones, and the aural warning source is connected to the pilot
Aug 25, 2005 Page 3-5
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