Northern Airborne Technology 251 - Manual (Page 5)

Model 251 Passenger Speaker Amplifier
SM251 Installation and Operation Manual
Section 1 Rev: 1.00 Issue 2 Page 1-2
ENG-FORM: 800-0115.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
1.4 Specifications
1.4.1 Electrical Specifications
Power Supply: 28 Vdc, 5 ampere maximum.
INPUTS:
ADF: Two individual, switched audio inputs for ADF1 and ADF2.
Input level is 7.75 Vrms.
PSC:
One switched audio input compatible with the Pilot Select COMM
output of dB Systems cockpit audio control amplifiers (such as
Models 438 and 700), which provides a 1.00 Vrms signal
produced from a summation of selected COMM, DME and MKR
receivers. The PSC input can also be used for TV audio or other
similar audio.
TV:
One switched audio input for TV (or other device). Input level is
1.00 Vrms.
Stereo Left:
One switched differential audio input for the left audio channel
from an AM/FM Stereo receiver/tape or CD deck (or other
device). Input level is maximum 0.45 Vrms. (at maximum source
volume) and audio LO is not common to that of other inputs.
Stereo Right:
Same as stereo left, switched by the same control input as
stereo left.
Brief:
One switched audio input for automated cabin briefer audio.
Input level is 1.00 Vrms.
PA MIC:
The microphone input used for cabin paging audio supplies bias
current and is compatible with carbon and amplified dynamic
microphones. Input level is 0.25 Vrms.
Paging Volume:
Controls level of PA MIC and brief audio inputs to the PA
sidetone and left and right speaker outputs. Volume control
range is 30 dB (minimum) controlled by a 10,000-ohm, 1/2-Watt,
linear pot. Maximum volume is with maximum resistance.
Receiver Volume:
Controls level of ADF, PSC and TV audio inputs to the left and
right speaker outputs. Volume control range is 30 dB (minimum)
controlled by a 10,000-ohm, 1/2-Watt, linear pot. Maximum
volume is with maximum resistance.