Northern Airborne Technology 240 User Manual

Installation and Operation Manual

Model 240

Passenger Speaker Amplifier

SM240

ISSUE 4.12

Northern Airborne Technology Ltd.

1925 Kirschner Road

Kelowna, BC, Canada.

Telephone [phone]

Facsimile [phone]

Issued on the authority of Northern Airborne Technology Ltd.

Copyright 2005

V1Y 4N7

Model 240 Passenger Speaker Amplifier

SM240 Installation and Operation Manual

Prepared By: Checked By: Certification: Approved By:

The status of this installation and operation manual is controlled by issue shown on the title page. The
status of each section is controlled by revision shown in the footer of each page. All revisions affecting
sections of this manual have been incorporated into the latest issue.

ISSUE/REVISION RECORD

Manual Issue

Number

4.12 Section 2 Rev: 1.01 MOD D WED label change May 26, 2010

Section

Revision Number

Revision Description Issue Date

4.11 Section 1 Rev: 1.00
Section 2 Rev: 1.00
Section 3 Rev: 1.00

4.10 N/A Initial release May 27, 2005

Rewritten in latest format Sep 8, 2008

Installation and Operation Manual Page ii

ENG-FORM: 820-0115.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

Model 240 Passenger Speaker Amplifier

SM240 Installation and Operation Manual

Table of Contents

Section Title Page

1. Description

1.1 Introduction 1-1

1.2 Product Description 1-1

1.3 Design Features 1-1

1.4 Specifications 1-1

1.4.1 Electrical Specifications 1-1

1.4.2 Physical Specifications 1-3

1.4.3 Environmental Specifications 1-3

1.4.4 Product Approval 1-3

1.5 Unit Nomenclature 1-3

2. Installation

2.1 Introduction 2-1

2.2 Unpacking and Inspection 2-1

2.2.1 Warranty 2-1

2.3 Continued Airworthiness 2-1

2.4 Installation Procedures 2-1

2.4.1 Warnings 2-2

2.4.2 Cautions 2-2

2.4.3 Cabling and Wiring 2-2

2.4.4 Mounting 2-2

2.4.5 Mode Selection 2-3

2.4.6 Numerical Pin Identification 2-3

2.4.7 Post Installation Checks 2-4

2.5 Adjustments and Connections 2-5

2.6 Accessories Required But Not Supplied 2-5

2.7 Installation Drawings 2-5

3. Operation

3.1 Introduction 3-1

3.2 General Information 3-1

Installation and Operation Manual Page iii

ENG-FORM: 820-0115.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

Model 240 Passenger Speaker Amplifier

SM240 Installation and Operation Manual

Section 1 Description

1.1 Introduction

Information in this section consists of product description, design features and specifications for the
Model 240 Passenger Speaker Amplifier. All derivative product information shall be contained in the
applicable manual supplement, which may be obtained from NAT as required.

Review all notes, warnings and cautions.

1.2 Product Description

The Model 240 Passenger Speaker Amplifier mixes audio from various sources for output to cabin
speakers. It is a remotely controlled, electronic unit, which operates upon command from switches and
potentiometers in the cockpit or cabin of the aircraft.

1.3 Design Features

The Model 240 provides left/right audio taken from an external stereo receiver/music source, to the cabin
speakers.

The Model 240 provides Fasten Seat Belt and No Smoking sign chime tones, a Cabin Call rin ger tone,
ADF, Pilot Select Com (PSC), TV, Briefer and Cabin Paging audio, to the cabin speakers.

All inputs and operating modes are electronically switched. Ground signals, supplied by manual switches
in the cockpit, enable the electronic switches in the Model 240. The circuitry is arranged to provide Paging
and Briefer audio priority; the PA MIC or Briefer switch signals essentially open the Stereo Left, Stereo
Right, ADF 1, ADF 2, PSC and TV audio inputs. Microphone bias current is available from the Model 240
for the PA MIC microphone input.

A musical chime tone is provided to the cabin speakers to alert the passengers of a change in the Faste n
Seat Belt or No Smoking sign status. A Cabin Call ringer tone is also provided to the cabin speakers for
the cockpit to cabin intercom system.

1.4 Specifications

1.4.1 Electrical Specifications

Input specifications are expressed in volts RMS (Vrms), rather than milliwatts, to avoid any misunderstanding.

Input Signals:

ADF: Two single, switched audio inputs f or ADF , etc. Inp ut level i s 7.75 V rms.
PSC: One single, switched audio input compatible with the Pilot Select

Com (PSC) output of dB Systems Model 418, which provides a

1.00 Vrms signal, produced from a summation of selected COM,
DME and MKR receivers.

TV: One single, switched audio input for TV etc. Input level is 1.00 Vrms.

Section 1 Rev: 1.00 Issue 4 Page 1-1

ENG-FORM: 800-0114.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

Model 240 Passenger Speaker Amplifier

SM240 Installation and Operation Manual

Stereo Left: One single, switched differential audio input from the Left channel of

the stereo audio from a stereo receiver/ music source. Input level is
maximum 1.00 Vrms (at max. source volume) and audio LO is not

Stereo Right: One single, switched differential audio input from the Right channel

Briefer: One single, switched audio input from Briefer audio, etc. Input level

PA MIC: The microphone input, used for Cabin Paging audio, supplies bias

Paging Volume: Controls the level of PA MIC and Briefer audio inputs to the PA

Receiver Volume: Controls level of ADF, PSC and TV audio inputs to the Left and Right

Power Supply: 28 Vdc, 3A maximum.

Output Signals:

Left/Right Speaker: The Left and Right Speaker Amplifier output ratings are each

PA Sidetone: This output will deliver 6.7 mW into 600 Ohms continuously. Rated

Chime Tone: Gen e r a t e d a n d s u p p l i e d t o L e f t and Right Speaker outputs whe n 12 to 32

Ringer Tone: Generated and supplied to Left and Right Speaker outputs when a

Frequency Response: Stereo inputs to Speaker outputs – Flat within 3 dB from 85 Hz to

Harmonic Distortion: Less than 3 percent distortion, all outputs.
Isolation Between Channels: 60 dB, minimum.
Output Noise: Greater than 75dB below rated, all outputs.

Section 1 Rev: 1.00 Issue 4 Page 1-2

ENG-FORM: 800-0114.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

common to that of other inputs.

of the stereo audio from a stereo receiver/music source. Input level is
maximum 1.00 Vrms (at max. source volume) and audio LO is not
common to that of other inputs.

is 1.00 Vrms

current and is compatible with carbon and amplified dynamic
microphones.

Sidetone and Left and Right Speaker outputs. Volume control range
is 30 dB (minimum) controlled by a 10 kOhm ½ watt, linear
potentiometer. When the potentiometer is at maximum, the level is at
maximum.

Speaker outputs. Range and control same as Paging Volume
specification.

20 watts into 2 Ohms. This is a peak rating, intended for speech and
music. The continuous rating of the amplifier output is 2 watts into
2 Ohms for sine wave operation. Power ratings are as follows:

Load Rated Power Continuous Power
2 Ohm 20 W 2W
4 Ohm 10 W 1W

and continuous power ratings are the same.

Vdc is applied to and removed from connector pins P50-31 and P50-32.
Provides a 790 ±20 Hz tone, followed by a decaying 610 ±20 Hz tone.
Factory set for 3.5 VP-P into 2 Ohms, adjustable from 1.0 to 6.9 VP-P.

ground signal is applied to connector pin P50-33. 700 ±75 Hz tone,
ON for 1.8 ±0.1 seconds, then OFF for 3.2 ±0.1 seconds, repeating.
Factory set for 1.5 VP-P (700 Hz component) into 2 Ohms,
adjustable from 0 to 5.2 VP-P.

20,000 Hz. All other inputs to Speaker or PA Sidetone outputs – Flat
within 3 dB from 350 Hz to 6,000 Hz.

Model 240 Passenger Speaker Amplifier

SM240 Installation and Operation Manual

1.4.2 Physical Specifications

1.4.3 Environmental Specifications

Note: Refer to Environmental Qualification Form located in Section 2 of this Manual for complete details

Height: 1.90" [48.26 mm]
Length: 7.80" [198.12 mm]
Width: 4.90" [124.46 mm]
Weight: 1.4 lbs. [0.635 kg]

Temperature: -55 to +70 degrees C.
Altitude: up to 70,000 feet.

Qualification of the Model 240 Passenger Speaker Amplifier was completed in accordance with
DO-160 B Env. Cat. F2-BA[JLO]XXXXXXX[BZ]AAAAAL

of the environmental categories.

1.4.4 Product Approval

FAA: TSO – C50c (RTCA/DO-170 Class Ib)

1.5 Unit Nomenclature

Model 240 Derivative Part Number Descriptions:
The following is a tabulation of all Derivative Part Numbers available for the Model 240 Passenger Speaker

Amplifier. A Model 240 with an associated Derivative Part Number is designated as a Model 240-xxx, where xxx
is the applicable three digit Derivative Part Number.

Derivative Part No. Description of Derivative

240-001

Physically and electrically identical to base Model 240 except for the following
changes:

Left and Right SPKR level shall be 3.3 ±6 Vrms.
Minimum RCVR volume shall be ≤100mVrms.
The Cabin Call Left and Right SPKR levels shall be 8 ±2 Vpp.
The Seat Belt/No Smoking Chime Left and Right SPKR levels shall be 1.6 ±2 Vpp.
Right and Left SPKR crosstalk shall be ≤7mVrms.
Right and Left SPKR noise shall be ≤4mVrms.

240-002 Physically and electrically identical to the Base Model 240.

Section 1 ends

Section 1 Rev: 1.00 Issue 4 Page 1-3

ENG-FORM: 800-0114.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.