Amron 2820A User manual

User Manual
For
Amron International, Inc.
Model 2820A-XX & 2825A-XX Series
Portable Two Diver Communicators
S/N ____________________
1380 Aspen Way, Vista California 92081-8349
United States of America
Phone: [phone]
Fax [phone]
Email: [e-mail]
Web: www.amronintl.com
This manual and the information contained herein are provided for use as an operation and maintenance
guide. No license or rights to manufacture, reproduce, or sell either the manual or articles described
herein are given. Amron International, Inc. reserves the right to change specifications without notice.
Copyright© 2020 Amron International, Inc.

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TABLE OF CONTENTS
1INTRODUCTION AND SPECIFICATIONS ..........................................................................................1
1.1 INTRODUCTION...........................................................................................................................1
1.2 SPECIFICATIONS ........................................................................................................................1
1.3 BATTERY LIFE.............................................................................................................................2
1.4 MATERIALS, WEIGHTS & DIMENSIONS....................................................................................2
2OPTIONS AND ACCESSORIES..........................................................................................................3
2.1 OPTIONS......................................................................................................................................3
2.2 ACCESSORIES ............................................................................................................................3
3CONTROLS AND CONNECTIONS......................................................................................................5
3.1 TENDER CONTROLS & CONNECTIONS ...................................................................................5
3.2 DIVER CONTROLS & CONNECTIONS.......................................................................................8
3.3 HELIUM SPEECH UNSCRAMBLER (DSP3) CONTROLS..........................................................9
3.4 WIRELESS TENDER (28B) CONTROLS...................................................................................10
3.5 DRAWING, 2-WIRE CONNECTIONS.........................................................................................11
3.6 DRAWING, FULL DUPLEX (4-WIRE) CONNECTIONS.............................................................12
3.7 DRAWING, OPERATOR CONNECTIONS, HAND HELD MICROPHONE................................13
3.8 DRAWING, OPERATOR CONNECTIONS, HEADSET..............................................................14
4OPERATION.......................................................................................................................................15
4.1 BATTERY CHARGING ...............................................................................................................15
4.2 BATTERY CONDITION ..............................................................................................................16
4.3 BATTERY INSTALLATION.........................................................................................................16
4.4 MODES OF OPERATION...........................................................................................................16
4.5 VOLUME CONTROLS (2-WIRE)................................................................................................18
4.6 VOLUME CONTROLS FULL DUPLEX (4-WIRE).......................................................................18
4.7 HELIUM SPEECH UNSCRAMBLER OPTION...........................................................................19
5MAINTENANCE AND TROUBLESHOOTING...................................................................................23
5.1 FULL DUPLEX (4-WIRE) CHECK ..............................................................................................23
5.2 2-WIRE CHECK..........................................................................................................................23
5.3 GENERAL MAINTENANCE........................................................................................................24
5.4 RECOMMENDED MAINTENANCE SCHEDULE.......................................................................24
5.5 TROUBLESHOOTING................................................................................................................26
6DRAWINGS ........................................................................................................................................29
6.1 PARTS IDENTIFIER, MODEL 2820A-11 WEATHER RESISTANT AC POWER MODULE......30
6.2 PARTS IDENTIFIER, MODEL 2825A-11 WEATHER RESISTANT AC POWER MODULE......31
6.3 PARTS IDENTIFIER, MODEL 2825A-12 WEATHER RESISTANT AC POWER MODULE &
DSP3 HELIUM SPEECH UNSCRAMBLER ...............................................................................32
6.4 PARTS IDENTIFIER, MODEL 2825A-13 WEATHER RESISTANT AC POWER MODULE & 28B
WIRELESS TENDER..................................................................................................................33

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7PARTS LISTS.....................................................................................................................................34
7.1 PARTS LIST FOR 282XA-XX SERIES FRONT PANEL ASSEMBLIES.....................................34
7.2 PARTS LIST, MODEL 2820A-11, WEATHER RESISTANT AC POWER MODULE .................35
7.3 PARTS LIST, MODEL 2825A-11, WEATHER RESISTANT AC POWER MODULE .................35
7.4 PARTS LIST, MODEL 2825A-12, WEATHER RESISTANT AC POWER MODULE & DSP3
HELIUM UNSCRAMBLER OPTION...........................................................................................35
7.5 PARTS LIST, MODEL 2825A-13, WEATHER RESISTANT AC POWER MODULE & 28B
WIRELESS TENDER OPTION...................................................................................................36
7.6 PARTS LIST, 2820-302 CASE ASSEMBLY WITH POWER ENTRY MODULE ........................36
7.7 28XXA-FS-02 FIELD SPARES KIT FOR 2820A, 2825A............................................................36
8LIMITED WARRANTY AND SERVICE POLICY................................................................................38

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1 INTRODUCTION AND SPECIFICATIONS
1.1 INTRODUCTION
Congratulations on purchasing the most advanced and powerful portable communicator in
the diving industry! Our engineering team has integrated the latest in digital advancements to
produce the industry’s most intelligible and reliable diver communicators. Our built-in quality
that Amron is known for makes the 2820A & 2825A series the most versatile and durable
communicators anywhere in the world!
The AMCOM II Series is a family of full-featured hard-wired, two-diver communicators. The
AMCOM II is offered in two basic versions. The units are identical except the Model 2825A
series has independent microphone and earphone volume controls for each diver and the
tender. The 2820A series has a single earphone volume control for diver’s volume (down-
link) and a single volume control for the tender (up-link).
All models come standard with a built-in internal charger and can be operated from either a
90-264 VAC, internal 12 VDC battery, or an external 12 VDC power source.
All communicators are supplied with an outdoor weather resistant AC power entry module
located on the case, and country specific locking AC power cord of your choice.
There are options available to fit your application such as DSP3 Helium Speech Unscrambler
and 28B Wireless Tender.
The 2820A-XX and 2825A-XX series has the ability to operate in the 2-Wire and Full Duplex
(4-Wire) mode, as well as both modes being used simultaneously. Full Duplex (4-Wire) mode
is required when using the Inhalation Noise Reduction or Wireless Tender features.
Only Amron offers Microphone Auto Detection that identifies the type of microphone each
diver is using and automatically adjusts for optimum performance. This portable diving
communicator has the ability to work with both dynamic and pre-amplified microphones in
either 2-Wire or 4-Wire modes.
1.2 SPECIFICATIONS
Input Impedance (Each Input) ................................................................................... 250 Ohms
Frequency Response ........................................................................................ 300 - 10000 Hz
Common Mode Rejection ..................................................................................40 dB Minimum
Current Drain Maximum Full Volume .............................................................................3 Amps
Minimum Quiescent ................................................................................................ 0.190 Amps
Output Impedance ........................................................................................................... 4 Ohm
Power Supply Voltage ..............................................12 VDC Nominal (9 VDC Min - 16 VDC Max)
AC Power Operating Range .................................................................... 90-264 VAC, 50-60 Hz
Sensitivity (Input) .............................................................................................................0.5 mV
Output Power (RMS @ 4 Ohm Load, 12 VDC) ..................................................10 Watts Audio

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1.3 BATTERY LIFE
Model 2820A-11 ........................................................................................................... 45 Hours
Model 2825A-11 .......................................................................................................... 45 Hours
Model 2825A-12 ........................................................................................................... 31 Hours
Model 2825A-13 ........................................................................................................... 32 Hours
1.4 MATERIALS, WEIGHTS & DIMENSIONS
Front Panel...............................................................................Stainless Steel, Powder Coated
Enclosure................................................................................High Impact UV Resistant Plastic
Enclosure Color.................................................................................Bright International Yellow
Length ..........................................................................................................14.5 In. (36.8 Cm)
Width ............................................................................................................9.0 In. (22.9 Cm)
Height ..........................................................................................................10.0 In. (25.4 Cm)
Model 2820A-11 with AC Power Module and Internal Charger ................. 16.25 Lbs. (7.37 Kg)
Model 2825A-11 with AC Power Module and Internal Charger ................. 16.95 Lbs. (7.69 Kg)
Model 2825A-12 with DSP3 Helium Speech Unscrambler Option............. 17.25 Lbs. (7.82 Kg)
Model 2825A-13 with 28B Wireless Tender Option ................................... 17.15 Lbs. (7.78 Kg)

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2 OPTIONS AND ACCESSORIES
The following options are available to customize the 2825A Series AMCOM communicators. Options
have to be ordered at the time of purchase or the communicator has to be returned to AMRON for the
option to be installed.
2.1 OPTIONS
-11 AC POWER WITH INTERNAL CHARGER
Commercial styletwo diver rechargeable communicator with binding posts comes
standard with AC power module, country specific locking power cord, and hand
held microphone.
2.1.1 -12 HELIUM SPEECH UNSCRAMBLER (HSU)
The communicator has all the features of the Model 2825A-11 plus Amron’s DSP3
Helium Speech Unscrambler (HSU) using the state-of-the-art Digital Signal
Processor (DSP) technology to correct raw helium speech into clear, intelligible
voice. This option includes a complex noise reduction filter to improve
communications in situations with high background noise levels.
-13 WIRELESS TENDER OPTION
The communicator has all the features of the Model 2825A-11 plus the wireless
tender option. The wireless option includes communicator master module, remote
module, remote module charger, remote wireless tender headset, remote ultra-light
headset, and carrying case. The wireless tender option allows the tender freedom
to move around up to 200 feet from the communicator. The wireless tender option
does require the divers to be wired in Full Duplex (4-Wire) mode.
2.2 ACCESSORIES
The following accessories are available for the AMCOM III communicator. Accessories can
be ordered at any time.
2.2.1 Item No. 2401-28 AMRON HEAVY-DUTY HEADSET (Dual Ear Muffs)
The Model 2401-28 is a high quality heavy-duty Telex headset with dual ear muffs
and boom microphone. It has superior sound quality and comes equipped with
color-coded dual banana plugs, 6-foot (1.8-meter) cord, and mates directly to
communicator.
2.2.2 Item No. 2401SM-28 AMRON HEAVY-DUTY HEADSET (Single Ear Muff)
The Model 2401SM-28 is a high quality heavy-duty Telex headset with a single ear
muff and boom microphone. It has superior sound quality and comes equipped with
color-coded dual banana plugs, 6-foot (1.8-meter) cord, and mates directly to
communicator.
2.2.3 Item No. 2460-28 AMRON STANDARD HEADSET (Dual Ear Muffs)
The Model 2460-28 is a light and comfortable headset with dual ear muffs and
designed for extended wear at an economical price. It comes equipped with color-
coded, dual banana plugs that mate directly to AMCOM diver communicators. The
spiral cord can extend up to 8 feet (2.4 meters).

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2.2.4 Item No. 2460SM-28 AMRON STANDARD HEADSET (Single Ear Muff)
The Model 2460-28 is a light and comfortable headset with a single ear muff and
designed for extended wear at an economical price. It comes equipped with color-
coded, dual banana plugs that mate directly to AMCOM diver communicators. The
spiral cord can extend up to 8 feet (2.4 meters).
2.2.5 Item No. 2490-28 NOISE REDUCTION HEADSET (Dual Ear Muffs)
The Model 2490-28 Active Noise Reduction (ANR) headset isolates and reduces
topside noise in loud environments dramatically, allowing the tender and divers to
communicate more clearly and comfortably with increased intelligibility.
Amron’s Active Noise Reduction Headset features two key technologies,
unmatched active noise reduction and unique dynamic noise cancelling
microphone. The proprietary electronic circuitry design shapes and equalizes
incoming audio signals to provide a clean full sound quality that enhances
intelligibility of the intercom audio.
The headset comes equipped with dual ear muffs, color-coded dual banana plugs,
6-foot (1.8-meter) cord, and mates directly to the communicator.
2.2.6 Item No. 2490SM-28 NOISE REDUCTION HEADSET (Single Ear Muff)
The Model 2490SM-28 Active Noise Reduction (ANR) headset isolates and
reduces topside noise in loud environments dramatically, allowing the tender and
divers to communicate more clearly and comfortably with increased intelligibility.
Amron’s Active Noise Reduction Headset features two key technologies,
unmatched active noise reduction and unique dynamic noise cancelling
microphone. The proprietary electronic circuitry design shapes and equalizes
incoming audio signals to provide a clean full sound quality that enhances
intelligibility of the intercom audio.
The headset comes equipped with a single ear muff, color-coded dual banana
plugs, 6-foot (1.8-meter) cord, and mates directly to the communicator.
2.2.7 Item No. 2405-28 AMRON PUSH-TO-TALK MIC
The Model 2405-28 is a dynamic hand-held push-to-talk microphone that provides
excellent sound quality to the diver. It comes equipped with a spiral cord that can
extend up to 6 feet (1.8 meters).
2.2.8 Item No. 2405NC-28 AMRON NOISE CANCELLING PUSH-TO-TALK MIC
The Model 2405-28 is a noise cancelling hand-held push-to-talk microphone that
provides excellent sound quality to the diver. It comes equipped with a spiral cord
that can extend up to 6 feet (1.8 meters).
2.2.9 Item No. 2822-28 AMRON REMOTE WALK-AND-TALK MODULE

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Designed for Full Duplex (4-Wire) applications, the Model 2822-28 provides the
tender with mobility around the dive site while maintaining communications with the
diver. It comes equipped with a small clip-on belt module that contains the
connectors for the headset, and 25 feet (7.6 meters) of lightweight flexible cable.
Custom cable lengths are available upon request.
2.2.10 Item No. 2821-28 AMRON REMOTE PUSH-TO-TALK MODULE
Designed for 2-Wire applications, the Model 2821-28 provides the tender with
mobility around the dive site while maintaining communications with the diver. It
comes equipped with a small clip-on belt module that contains a push-to-talk
switch, connector for the headset, and 25 feet (7.6 meters) of lightweight flexible
cable. Custom cable lengths are available upon request.
2.2.11 Item No. 190-0650-01 AMRON WIRELESS TENDER HEADSET (Single Ear Muff)
A single ear muff headset that is compatible with the 28B Wireless Tender option.
Additional headsets can be ordered to allow other crew members, supervisors,
crane operators, etc. to monitor the conversation.
2.2.12 Item No. 190-0650-02 AMRON WIRELESS TENDER HEADSET (Dual Ear Muffs)
Dual ear muffs headset that is compatible with the 28B Wireless Tender option.
Additional headsets can be ordered to allow other crew members, supervisors,
crane operators, etc. to monitor the conversation.
3 CONTROLS AND CONNECTIONS
Before using the AMCOM II series diver communications system, you should familiarize yourself with
its operating controls and connections. Improper use of controls and connections will deprive the user
of the full benefits of this communication system.
3.1 TENDER CONTROLS & CONNECTIONS
3.1.1 AC POWER LED to identify the presence of AC power. When the communicator is
plugged into AC power, the Green LED will be on regardless if the communicators
POWER SWITCH is on or off.
3.1.2 POWER SWITCH –controls power to the communicator.
3.1.3 SPEAKER SWITCH –allows the tender to turn off the speaker. If the tender is
using a headset, it may be necessary to turn off the speaker in order to prevent
acoustic feedback.
3.1.4 PUSH-TO-TALK (ALL DIVERS) –allows the tender to talk to all the divers when
operating in the 2-Wire mode. It is not necessary to use this control in the Full
Duplex (4-Wire) mode and tender wearing a headset.
3.1.5 TENDER MICROPHONE VOLUME (2825A series only) – controls the volume level
for the tender's microphone and/or PANEL MICROPHONE. Rotate knob clockwise
to increase the tender’s volume to all the divers.

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3.1.6 TENDER EARPHONE VOLUME –controls the volume level for the tender's
earphone and/or PANEL SPEAKER. Rotate this knob clockwise to increase the
volume from all the divers
3.1.7 BATTERY CONDITION INDICATOR – a steady GREEN LED light indicates
battery charge level is good. Blinking GREEN LED light indicates battery charge
level is at a low level with less than 3 hours of running time available. Steady RED
LED light indicates battery charge level is below the level necessary to guarantee
proper operation.
WARNING: When BATTERY CONDITION INDICATOR is steady RED LED light,
the batteries should be replaced or recharged immediately.
3.1.8 PANEL SPEAKER – is a waterproof acoustic horn speaker that allows the tender
to listen to the divers. The volume level is controlled by the EARPHONE VOLUME
controls and it can be turned off using the SPEAKER SWITCH.
3.1.9 PANEL MICROPHONE – is a water-resistant condenser microphone that allows
the tender to talk to the divers using the PUSH-TO-TALK BUTTONS. The volume
level is controlled by the MICROPHONE VOLUME controls. The PANEL
MICROPHONE is muted when the SPEAKER SWITCH is turned off.
WARNING: Do not plug or cover the PANEL MICROPHONE hole. This may
reduce or eliminate the tender-to-diver communications, and possibly
damage the microphone.
3.1.10 TENDER HEADSET JACKS (BLACK) –are dual banana jacks (color-coded black)
that functions as both an output (earphone) and input (microphone) for the tender
as controlled by the PUSH-TO-TALK BUTTON and PUSH-TO-TALK JACK. Using
this connection, the tender can be wired in either 2-Wire or Full Duplex (4-Wire)
mode regardless of the mode used for the diver.
To connect the tender in the Full Duplex (4-Wire) mode, connect the earphone
(black) banana plug of the headset to this jack and the microphone (red) to the
TENDER MICROPHONE jack (red) as shown in wiring diagram section 3.6. In this
mode, the tender does not have to use the PUSH-TO-TALK BUTTON to
communicate with a diver who is also connected in the Full Duplex (4-Wire) mode.
This configuration can be used even if the diver is connected in 2-Wire mode. In
that situation, the tender is required to use the PUSH-TO-TALK BUTTON or
PUSH-TO-TALK JACK.
The headset microphone is always active, which means that there can be acoustic
feedback between the PANEL SPEAKER and the microphone if the tender is near
the communicator. To prevent this, the PANEL SPEAKER can be turned off using
the SPEAKER SWITCH. Another option is to move the tender away from the
communicator by using the Amron Model 2822-28 Walk-and-Talk Module
accessory. This allows the tender to communicate while other members of the
surface crew listen using the PANEL SPEAKER. This module comes with 25 feet
(7.6 meters) of cable (custom cable lengths are available).