802-009 Switch Panel
SM802 Installation and Operation Manual
Section 2 Rev: 1.01
Issue 4
Page 2-4
ENG-FORM: 805-0121.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
HAND MIC
The HAND MIC input, intended for the hand held microphone, is compatible with carbon
and amplified dynamic microphones. It receives its bias current from the Model 700
amplifier through the 802-009 to Model 700 HOT MIC connection. This input may be
used for transmitting only and not for interphone communications. A transmitter is keyed
for this mic input using the PTT switch on the hand held microphone.
2.4.5.2
OUTPUTS
HOT MIC
A HOT MIC microphone output is provided on the 802-009 to make this connection to the
Model 700 HOT MIC input. This connects any one selected microphone input (NORM,
OXY, or HAND) directly to the Model 700 HOT MIC input, which channels the
microphone audio to the Model 700 cockpit voice recorder (CVR) output for hot
microphone recording purposes. The HOT MIC input of the Model 700 Amplifier is also
used for interphone communication with the NORM and OXY MIC inputs when the INPH
switch on the 802-009 is turned ON. The HAND MIC input is used for transmitting or PA
only and not for interphone communications.
TX & PA MICs During a transmit PTT, these outputs are simply a direct connection from the microphone
input being used to the selected transmitter or PA mic output. The mic audio input is
connected to the output selected by the MIC SELECT switch on the switch panel. These
outputs are intended for connection to respective transmitter and PA amplifier mic inputs.
MUX DATA
This output is a RS422 differential data transmission line driver intended for connection to
the Model 700 amplifier MUX DATA input. It transfers all of the digital data necessary to
control Model 700 functions via a shielded twisted-pair wire cable up to 4,000 feet long.
2.4.5.3
VOLUME CONTROLS
RECEIVERS
These volume controls are linear taper potentiometers connected internally to the digital
multiplexing circuitry. Volume control range and curve are defined in Model 700 amplifier
software.
INPH
Same as RECEIVERS volume.
PHONE
Same as RECEIVERS volume.
SPKR
Same as RECEIVERS volume.
PASS/
The PASS volume knob controls the level of the PA amplifier output only when the MIC
BRIEFER
SELECT Switch is in the PASS position. This is a 10 k
Ω
, 0.5 W, linear taper
potentiometer connected through relay switching logic to pin P1-14 of the Model 802.
Maximum volume position (fully clockwise) provides maximum resistance. Volume control
range and curve are determined by PA amplifier circuitry. Refer to Section 2.4.5 for more
details.
2.4.5.4
ANTENNA SWITCHING
P1-32 should be connected to 28 VDC or ground to suit the requirements of the Antenna Switching Unit.
When the MIC SELECT switch is in the HF1 position, P1-32 and P1-6 are connected internally. When the
MIC SELECT switch is in the HF2 position, P1-32 and P1-16 are connected internally.
