COBHAM 700 Equipment Manual

DOCUMENT NUMBER 700-16-1 REVISION 1.10

SEALED

2010.10.26 
10:42:26 

-07'00'

EQUIPMENT MANUAL

Product Functional Specifications

and Installation Manual

DIGITAL AUDIO CONTROL AMPLIFIER

MODEL 700-[ ]

AND

ALL DETAIL PART NUMBERS

For Cobham Use Only

IMPORTANT NOTICE
Chelton Avionics Inc. doing business as
Wulfsberg Electronics Inc. doing business as
Cobham Avionics will be responsible for full
distribution and revisions of ICA's (Instructions
for Continued Airworthiness).

CONFIDENTIAL AND PROPRIETARY TO COBHAM

EQUIPMENT MANUAL 700-16-1 REV 1.10

Geoff Melton

2010.10.06 
14:26:32 -07'00'

Edward 
Uy

2010.10
.11 
12:24:3
7 -07'00'

Zack Pahlman

2010.10.25 13:49:30 

-07'00'

CHANGE RECORD

DATE CHANGE CHECK APPROVAL

3-11-03

4-13-05

10-20-05

11-1-05

ORIGINAL DOCUMENT RELEASED

REVISION A:

Throughout this document: NAT Seattle was
dB Systems. (Type IV)

Incorporated 700-008 to Table A. (Type IV)

REVISION B:

Section 1.0: Added TSO installation limitation
statement.

Figure 3: Changed title to “generic”. Revised
Figure 3 drawing to show Model 80x Switch
Panels, 700-xxx Digital Audio Control
Amplifier, and 630-xxx Aural Warning
Generator.

(Type IV)

REVISION C:

Table A:

700-008 MOD status was listed as No MOD
(typo). (Type IV)

AP AP

SS AP

SF AP

SF ZHP

06-29-09

SEE TITLE

PAGE

REVISION 1.04:

Incorp. ECR2 700-16. Added Model 700-009
to Table A. Updated NAT logo. Added
Confidential and Proprietary notice.

REVISION 1.10:

Incorporated ECR3 700-16. Updated Figure
1 to current rev. Cobham was NAT Seattle.
Added ICA responsibility notice to front
cover.

SC AP

700/700-16-1

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Page a

EQUIPMENT MANUAL 700-16-1 REV 1.10

TABLE OF CONTENTS

Page

MODEL 700 DETAIL PART NUMBER DESCRIPTIONS..........................................c

1.0 OPERATING INSTRUCTIONS AND EQUIPMENT LIMITATIONS.................1

2.0 SPECIFICATIONS.........................................................................................3

3.0 INSTALLATION PROCEDURES, WIRING DIAGRAMS,

AND LIMITATIONS........................................................................................6

3.1 PHYSICAL DESCRIPTION....................................................................6

3.2 ELECTRICAL DESCRIPTION...............................................................6

4.0 CALIBRATION AND MAINTENANCE PROCEDURES..................................7

Tables

Table A Detail Part Numbers....................................................................................c

Table 1 Pin Identification List, Numerical..................................................................7

Table 2 Environmental Qualification Form ................................................................15

Figures

Figure 1 Outline, Model 700 and all detail part numbers...........................................8

Figure 2 Model 700 Wiring Diagram .........................................................................9

Figure 3 Typical Model 700 installation schematic....................................................12

Figure 4 Mounting Rack for Model 700, S-TEC P/N 628-7558-001...........................14

700/700-16-1

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Page b

EQUIPMENT MANUAL 700-16-1 REV 1.10

MODEL 700 DETAIL PART NUMBER DESCIRIPTIONS

The detail part numbers associated with the Model 700 Digital Audio Control Amplifier may define
different level adjustments or test procedures than those outlined in dB Systems’ Document
Number 700-4 and this document. Table A describes those differences.
NOTE: A Model 700 with an associated detail part number is designated as a Model 700-XXX,

where XXX is the applicable detail part number.

Table A. Detail Part Numbers

Detail Part Number Description of Detail

Basemodel 700 Base model. MOD status C. Reference Appendix A.

001 DELETED

002 Physically and electrically identical to base Model 700;

designated for Learjet Model 60 levels. Levels no different than
those of base Model 700.

Throughout this document:

- Substitute "Model 700-002" in place of references to
"Model 700."

MOD status: B

003 Levels set for special mission Learjet 35 with 4-station

interphone.

Throughout this document:

- Substitute "Model 700-003" in place of references to
"Model 700."

MOD status: B

004 Levels set for special mission Hawker U125A with 6-station

interphone and customized receiver levels.

Throughout this document:

- Substitute "Model 700-004" in place of references to
"Model 700."

MOD status: C

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Page c

Table A. Detail Part Numbers (continued)

Detail Part Number Description of Detail

005 Physically and electrically identical to base Model 700;

designated for Raytheon Hawker 800XP. Levels no different
than those of base Model 700.

Throughout this document:

- Substitute "Model 700-005" in place of references to
"Model 700."

MOD status: D

006 Designated for Raytheon PFP3 King Air. Levels no different

than those of base Model 700. No difference in test procedure

Throughout this document:

- Substitute "Model 700-006" in place of references to
"Model 700."

EQUIPMENT MANUAL 700-16-1 REV 1.10

MOD status: B

007 Calibrated for Raytheon Hawker 800XP

Throughout this document:

- Substitute "Model 700-007" in place of references to
"Model 700."

MOD status: C

008

Calibrated for Raytheon Premier 1.

Throughout this document:

- Substitute "Model 700-008" in place of references to
"Model 700."

MOD status: A

009

Calibrated for Raytheon Hawker 400XPI.

Throughout this document:

- Substitute "Model 700-009" in place of references to
"Model 700."

- Reference Appendix I.

700/700-16-1

MOD status: None

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Page d

EQUIPMENT MANUAL 700-16-1

EQUPMENT MANUAL

MODEL 700-[ ]

1.0 OPERATING INSTRUCTIONS AND EQUIPMENT LIMITATIONS

This document makes references to dB Systems, Inc. and NAT Seattle, Inc. Please note that
dB Systems, Inc. and NAT Seattle, Inc. have been changed to Cobham. For all references to
dB Systems, Inc. or NAT Seattle, Inc. herein, substitute Cobham.

The conditions and tests required for TSO approval of this article are minimum performance
standards. It is the responsibility of those installing this article either on or within a specific type
or class of aircraft to determine that the aircraft installation conditions are within the TSO
standards. TSO articles must have separate approval for installation in an aircraft. The article
may be installed only if performed under 14 CFR part 43 or the applicable airworthiness
requirements.

The Model 700 Digital Audio Control Amplifier is a remotely controlled electronic unit that operates
upon digital signal command sent to it by the digital multiplexing unit or switch panel at its
respective audio control station. An example of such a switch panel would be Model 803. The
digital multiplexing unit or switch panel continuously reads the status of all audio control switches
and settings of potentiometers and compiles this information into the form of a digital signal. The
digital signal is sent to the Model 700 from the digital multiplexing unit or switch panel in RS-422
serial format via a twisted, shielded wire pair. The Model 700 receives and demultiplexes this
digital signal and converts it into useful audio control information.

The Model 700 is capable of switching and controlling the individual volume of up to 15 receiver
inputs. It also switches six sidetone inputs and an interphone line. In addition, four unswitched
and unmuted inputs are provided to accommodate an aural warning input and three auxiliary
inputs. Headphone and selected speaker outputs are isolated and a cockpit voice recorder (CVR)
output is a summation of the headphone and Hot microphone audio. The Hot microphone to CVR
audio channel is unswitched and unmuted, thus allowing Hot microphone audio to be recorded on
the cockpit voice recorder at all times. A pilot select COMM output is a summation of all selected
receiver inputs, excluding aural warning, auxiliary, sidetone, or interphone audio.

Receiver, sidetone, headphone, interphone and speaker audio, and all operating modes are
electronically switched and controlled by the digital signal information sent from the digital
multiplexing unit or switch panel. An electronic volume control attenuator is employed in each of
the 15 receiver audio input channels. Every receiver input attenuator has 25 dB of range and is
digitally controlled. Separate electronic volume control attenuators are provided for headphone
audio (35 dB range), speaker audio (35 dB range), sidetone audio (25 dB range), and interphone
audio (25 dB range). These volume control attenuators are also digitally controlled. Refer to the
applicable multiplexing unit or switch panel equipment manual for specific information on control
hardware required. Aural warning, auxiliary, CVR, and pilot select COMM audio channels do not
employ any individual electronic volume control attenuators; however, the volume of some CVR
audio is directly affected by the headphone volume control.

A voice activated switch (VAS or VOX) is incorporated in series with the Hot microphone input to
interphone channel. This feature allows Hot interphone operation without coupling of ambient
cockpit noise into the amplifier during times when the pilot is not talking. If the internal VAS pot
jumper is installed at the mating connector (see Figure 2, Wiring Diagram), then the threshold of
voice activation may be adjusted by an internal screwdriver adjustment through a hole in the cover

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EQUIPMENT MANUAL 700-16-1

labeled "VOX THLD." It is factory set at 100 millivolts and adjustable from 30 to 350 millivolts.
The VAS is not incorporated in series with the Hot microphone input to CVR output channel.

Selective voice or ident code filtering is provided on four of the receiver audio inputs, intended for
NAV and ADF audio. The filter function is also digitally controlled.

The speaker amplifier in the Model 700 is rated at 10 Watts into 4 ohms. This is a peak rating
intended for speech and music. The continuous rating of the amplifier is 1 Watt into 4 ohms for
sine wave operation. The speaker channel is powered through an internal fuse, separate from the
headphone channel, so that a severe failure of the speaker channel will not simultaneously
disable the headphone channel.

All outputs (including the headphone and speaker outputs) of the Model 700 are both open and
short circuit protected.

All internal screwdriver potentiometer adjustments of the Model 700 are set to factory standards.
Some adjustments can be made through access holes in the cover. If it is necessary to change a
setting, refer to Section II of this manual.

The amplifiers are adjusted for acceptable listening output levels into the proper loads with
receiver inputs of 7.75 volts RMS. This input level is realized when receivers are set for 100
milliwatts into 600 ohms. If 7.75 volts RMS is greatly exceeded at the inputs, the audio will
become distorted due to peak clipping and audio bleedthrough will be noticed. However, the
amplifiers will not be damaged. Input levels can vary with detail part number. Refer to ATP 700-4.

An important feature of the Model 700 is its two different emergency modes of operation. In the
first mode, when there is an interruption of supply power to the unit, the Model 700 will
automatically pass COMM-1 and COMM-1 sidetone audio through to the headphone output with
23 dB of attenuation into the 150-ohm headphone load. In the second mode of operation, when
there is no loss of supply power to the Model 700 but there is a loss of digital communications
between the digital multiplexing unit or switch panel and the Model 700, the Model 700
automatically turns ON COMM-1 and COMM-1 sidetone audio channels and turns OFF all other
receiver/sidetone inputs so that only COMM-1 communications can be heard on the headphone
output. During this mode of operation, headphone volume level is maintained at the same setting
realized immediately prior to loss of digital communications. Also, aural warning and auxiliary
audio is provided to the headphone and speaker outputs as normal. A loss of digital
communications can occur if the digital multiplexing unit or switch panel lose power or if the
twisted, shielded wire pair carrying digital information is somehow disconnected or severed.

Normal operating modes of the Model 700 are listed below and are established when the
appropriate digital multiplexing unit or switch panel digital signal is sent to the Model 700.

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