Acom 2S1 User manual

ACOM 2S1
Automatic XCVR Commutator
User's Manual
Installation, Operation
and Maintenance
June 2022
OUTSTANDING HF POWER PRODUCTS

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
Page 2of 32 | S e c t i o n ABOUT DOCUMENTATION
June 2022
This manual is for electronic distribution mainly.
If you have it on paper and you no longer need it, please, recycle it!
The latest versions of our User's Manuals are available at
www.acom-bg.com

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
June 2022
S e c t i o n ABOUT DOCUMENTATION | Page 3of 32
ABOUT DOCUMENTATION
All ACOM documentation (including manuals, brochures, specifications, descriptions, presentations, video
materials, etc.) are based on the latest available information at the time of creation of our documents.
As we always strive to constantly improve and update our products, ALL PRODUCTS, PRODUCT
SPECIFICATIONS AND DATA ARE SUBJECT TO CHANGE. ACOM reserves the right to make changes and
improvements at any time without further notice or obligation to notify any person or organization of such
revisions or changes, made in order to improve the reliability, function, quality and design, and/or
performance of the ACOM products and services.
Further, this User's Manual is provided AS IS and ACOM shall not be liable for possible errors contained
herein.
This manual supersedes all previous editions, which thereby become invalid.
The cover images used in the manual are illustrative only.
We are continuously striving to improve our documentation, but nobody is perfect.
And our documentation is not an exception of this rule.
Have you found any errors or would you like to suggest changes in our documentation?
Please help us by sending your suggestions to the following e-mail address:
[e-mail]
The latest versions of our User's Manuals are available at
www.acom-bg.com
We highly recommend you to use this manual in electronic form as PDF-file instead of printed version. The
PDF-file is easy to read on any computer, tablet, smart phone or other similar device. In the PDF file you will
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User's Manual | ACOM 2S1 | Automatic XCVR Commutator
Page 4of 32 | S e c t i o n ABOUT DOCUMENTATION
June 2022
Title of Documentation
ACOM 2S1 Automatic XCVR Commutator
User's Manual
Installation, Operation and Maintenance
Type of Documentation
User's Manual
Purpose of Documentation
This manual explains Installation, Operation and Maintenance of the
ACOM 2S1 Automatic XCVR Commutator.
Record of Revisions
Description
Release Date
Notes
ACOM 2S1 User's Manual
04.1999
First edition
ACOM 2S1 User's Manual
22.06.2022
Second edition, R01
Validity
The specified data is for product description purposes only and may not be
deemed to be guaranteed unless expressly confirmed in the contract. All
rights are reserved with respect to the content of this manual and the
availability of the product.
Copyrights
© 2022 ACOM Ltd.
Copying this document, giving it to others and the use or communication
of the contents thereof without express authority, are forbidden.
Offenders will be held liable for infringement of any intellectual property
of ACOM Ltd. and all damages which may rise as a result.
Trademarks
ICOM, KENWOOD, YAESU, ELECRAFT, and other product names or brands
mentioned in this documentation are either registered trademarks or
trademarks of their respective holders.
Published by
ACOM Ltd.
Bulgaria | Bozhurishte 2227
Sofia-Bozhurishte Industrial Park | 6 Valeri Petrov Str.
GPS coordinates: 42.748616о| 23.209801о
Web: www.acom-bg.com
E-mail: [e-mail]
Note
This manual has been printed on chlorine-free bleached paper.

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
June 2022
S e c t i o n ABOUT DOCUMENTATION | Page 5of 32
Contents
ABOUT DOCUMENTATION ................................................................................................................................ 3
1. GENERAL INFORMATION........................................................................................................................... 7
1.1. Introduction and Description.......................................................................................................... 7
1.2. Product History and Documentation Validity ................................................................................. 8
1.3. Owner Assistance............................................................................................................................ 9
1.4. Equipment Supplied........................................................................................................................ 9
1.5. Features......................................................................................................................................... 10
1.6. Safety Considerations, Explicit Definitions.................................................................................... 11
2. INSTALLATION.......................................................................................................................................... 14
2.1. Unpacking and Initial Inspection................................................................................................... 14
2.2. Commutator Location Selection.................................................................................................... 14
2.3. Connections................................................................................................................................... 14
3. INITIAL CHECK AND OPERATION ............................................................................................................. 19
4. MAINTENANCE ........................................................................................................................................ 21
4.1. Periodic Maintenance ................................................................................................................... 21
4.2. Cleaning......................................................................................................................................... 21
4.3. Schematic Diagram........................................................................................................................ 21
4.4. Troubleshooting ............................................................................................................................ 24
5. SPECIFICATIONS....................................................................................................................................... 25
5.1. Parameters.................................................................................................................................... 25
5.2. Functions....................................................................................................................................... 25
5.3. Regulatory Requirements ............................................................................................................. 26
5.4. Storage and Shipment................................................................................................................... 26
5.4.1. Storage Environment....................................................................................................... 26
5.4.2. Shipping Size and Weight ................................................................................................ 26
5.4.3. Transportation................................................................................................................. 26
5.4.4. Returning to the Service Provider ................................................................................... 26
5.5. Information on Disposing and Recycling of Old Electrical and Electronic Equipment.................. 28
NOTES.............................................................................................................................................................. 29

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Figures
Figure 1-1 | Production Version Release Date 11.1999 .................................................................................... 8
Figure 1-2 | Production Version Release Date 04.2022 .................................................................................... 8
Figure 2-1 | Rear panel - Connections............................................................................................................. 14
Figure 2-2 | Control cables YAESU FT-990 and FT-1000MP transceivers........................................................ 15
Figure 3-1 | Front panel - Indicators ............................................................................................................... 19
Figure 4-1 | Schematic diagram, Part 1........................................................................................................... 22
Figure 4-2 | Schematic diagram, Part 2........................................................................................................... 23
Tables
Table 1-1 | Production versions history............................................................................................................ 8
Table 1-2 | Package contents............................................................................................................................ 9
Table 2-1 | Control cable wiring for YAESU FT-990 and FT-1000MP transceivers.......................................... 16
Table 2-2 | Signals and pin out of the CONTROL A/B connector .................................................................... 17

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
June 2022
S e c t i o n GENERAL INFORMATION | Page 7of 32
1. GENERAL INFORMATION
Congratulations on purchasing of our exclusive ACOM 2S1 Automatic XCVR commutator.
ACOM is pleased that you have chosen one of our products, and we will endeavor to provide you with the
information and support you need to enjoy your purchase for many years.
We urge you to read all of the following materials before you embark on installing and using your new
ACOM 2S1 Automatic XCVR commutator.
1.1. Introduction and Description
This manual explains:
•Installation,
•Operation and
•Maintenance
of the ACOM 2S1 Automatic XCVR commutator.
The ACOM 2S1 is a TX/RX commutator that allows two transceivers to use a common load. It guards each
transceiver's input while the other transceiver transmits, prevents simultaneous transmission, and allows
simultaneous reception.
ACOM 2S1 commutator is especially designed to complete the ACOM 2000S/SW (ACOM
2000S automatic antenna selector plus ACOM 2000SW remote antenna switch) and the
ACOM 2000A automatic HF linear amplifier.
For details about ACOM 2000A, ACOM 2000S, and ACOM 2000SW, please, visit
www.acom-bg.com.
Nevertheless, ACOM 2S1 may be used to commutate an antenna only, or can be adapted in other systems,
too. Its operation is fully automatic and the full break-in (QSK) mode is standard.

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
Page 8of 32 | S e c t i o n GENERAL INFORMATION
June 2022
1.2. Product History and Documentation Validity
The ACOM 2S1 commutator serial production started in November 1999. The production has continued to
these days without functional changes and with hardware improvements only.
This manual refers to the ACOM 2S1 Automatic XCVR Commutator and describes the operating possibilities
of all commutators produced till the publishing date of this manual.
This manual is valid till a new manual is issued.
Table 1-1 | Production versions history
Production Version
Release Date
Notes
11.1999
Basic design, metal outside box in RAL 8019 color;
04.2022
New metal outside box (in black color); No functional changes;
Table 1-1 | Production versions history
Figure 1-1 | Production Version Release Date 11.1999
Figure 1-1 | Production Version Release Date 11.1999
Figure 1-2 | Production Version Release Date 04.2022
Figure 1-2 | Production Version Release Date 04.2022

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June 2022
S e c t i o n GENERAL INFORMATION | Page 9of 32
1.3. Owner Assistance
If assistance is needed, you should contact your local dealerfirst. If necessary, your dealer will contact ACOM
for additional guidance.
If you still have an issue you need to discuss with one of ACOM's specialists, the contact information is as
follows:
ACOM Ltd.
E-mail: [e-mail]
Bulgaria | Bozhurishte 2227
Sofia-Bozhurishte Industrial Park |6 Valeri Petrov Str.
GPS coordinates: 42.748616о| 23.209801о
1.4. Equipment Supplied
The ACOM 2S1 automatic XCVR commutator is shipped in a cardboard carton.
The ACOM 2S1 is shipped as package, consisting of:
Table 1-2 | Package contents
Nr.
PACKAGE CONTENTS
Pcs.
1
ACOM 2S1
1
2
Control cables*, 3 m
2
Table 1-2 | Package contents
The User's Manual is available as PDF-file only.
The latest version of the User's Manual is available at www.acom-bg.com.
NOTICE
* Control cables are directly suited for YAESU FT-990 and FT-1000MP transceivers
(BAND DATA connectors).
If any of your transceivers is different, you'll need to replace the 8-pin, DIN connector or
make a suitable adapter (see Section 1.1.d) CONTROL A and CONTROL B connectors).
Using an inappropriate cable may cause a serious damage to the ACOM 2S1 commutator
and your transceivers (not covered under warranty)!

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
Page 10 of 32 | S e c t i o n GENERAL INFORMATION
June 2022
1.5. Features
•Automatic operation
Operation is fully automatic and the full break-in (QSK) mode in CW is standard.
•Easy to use
The ACOM 2S1 may be used to commutate an antenna only or can be adapted in other systems, too.
ACOM 2S1 is especially designed to complete the ACOM 2000S automatic antenna selector and ACOM
2000SW remote antenna switch, and the ACOM 2000A automatic HF linear amplifier.
•Integrated power supply
There is no need of external power supply device. The ACOM 2S1 uses power supply directly from the
transceiver (11-14 VDC / 30 mA power supply).

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
June 2022
S e c t i o n GENERAL INFORMATION | Page 11 of 32
1.6. Safety Considerations, Explicit Definitions
The ACOM 2S1 commutator is intended for indoor use only.
The ACOM 2S1 automatic XCVR commutator is designed to meet international safety standards and
complies with the CE safety and electromagnetic compatibility requirements.
The ACOM 2S1 commutator is designed as low-power device that operates at normal room temperature
and do not require a protective-earth connection. The device is powered from 12 VDC (fed from
transceivers) and its consumption is below 30 mA.
This User's Manual contains information, warnings (signal words Danger, Warning, Caution and Notice)
and instructions, related to hazards, that should be followed by the user in order to ensure safe operation
and to keep the device in a safe working condition at all times.
The EXPLICIT DEFINITIONS described below apply to this User's Manual:
DANGER
These notes call attention to a procedure or instructions which, if not correctly
performed, will result in serious personal injuries and even death.
WARNING
These notes call attention to a procedure or instructions which, if not correctly
performed, could result in serious personal injuries and even death.
CAUTION
These notes call attention to a procedure or instructions which, if not correctly
performed, could result in minor or moderate personal injuries.
NOTICE
These notes call attention to a procedure or instructions which, if not correctly
performed, could result in property damage or equipment damage not exclusively to
the commutator but also to connected equipment.

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
Page 12 of 32 | S e c t i o n GENERAL INFORMATION
June 2022
Information notes described below apply to this User's Manual:
These notes highlight operating procedures or practices that may improve equipment
reliability and/or personnel performance, or to emphasize a concept.
ORANGE TEXT as LINKS
marks all internal links in the document between Sections, Figures, Tables, etc. for your
convenience.
The safety instructions contained in this User's Manual feature specific signal words
(Danger, Warning, Caution or Notice) and, where required, a safety alert symbol, in
accordance with actual standards ISO 3864 or ANSI Z535.

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
June 2022
S e c t i o n GENERAL INFORMATION | Page 13 of 32
PRECAUTIONS:
DANGER
NEVER TOUCH AN ANTENNA or antenna insulators during transmission or tuning - this
may result in an electric shock or burn. NEVER EXPOSE the commutator to rain, snow or
any liquids.
WARNING
Do not undertake on your own repairs or changes in hardware of the commutator in
order not to endanger your or other's health and life and not to damage the
commutator and the equipment connected with it, not covered by warranty. The
manufacturer is not liable for another's actions and responsibility shall be assumed by
the doer.
WARNING
To avoid damage (not covered under warranty) read the Section 2 INSTALLATION of this
User's Manual carefully. If you have any doubts about the installation or safety of the
device, please, consult your dealer.
NOTICE
Some types of transceivers are not suitable to be directly used in the ACOM 2S1 XCVR
commutator system. If your transceiver does not have TXINHIBIT input, it cannot be
suited to the ACOM 2S1 XCVR commutator system (unless any modification is made
inside the transceiver to get such TXINHIBIT input).
Check your transceiver's manual or consult your dealer.

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
Page 14 of 32 | S e c t i o n INSTALLATION
June 2022
2. INSTALLATION
2.1. Unpacking and Initial Inspection
Before you install your commutator, thoroughly read this manual.
First, carefully inspect the cardboard carton and its contents for physical damage.
ACOM ships commutator in protected container, but it cannot assure that mistreatment
by shippers will not occur. If damage is evident, notify your dealer immediately. Delay
may void the carrier's warranty.
Keep all packing materials for possible future commutator shipment (see Section 5.4.4 Returning to the
Service Provider).
2.2. Commutator Location Selection
Position the commutator near your transceivers or power amplifiers. You will need an easy access to the
LED indicators on the front panel, as well as to the rear panel cabling.
2.3. Connections
Please, see Figure 2-1 | Rear panel - Connections.
Connections to your stations must be accomplished in the order described below.
Figure 2-1 | Rear panel - Connections
Figure 2-1 | Rear panel - Connections
b)
c)
d)
e)
d)
a)
e)

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
June 2022
S e c t i o n INSTALLATION | Page 15 of 32
a) INPUT A connector
Connect a coaxial cable with a PL-259 plug from commutator INPUT A connector to the antenna connector
of transceiver A (see Figure 2-1 | Rear panel - Connections, Pos. (a)).
b) INPUT B connector
Connect a coaxial cable with a PL-259 plug from commutator INPUT B connector to the antenna connector
of transceiver B (see Figure 2-1 | Rear panel - Connections, Pos. (b)).
c) OUTPUT connector
Connect a coaxial cable with a PL-259 plug from the commutator OUTPUT connector to the common load
(amplifier's input, or antenna switch, or to the antenna directly, whichever is used). Please, see Figure 2-1 |
Rear panel - Connections, Pos. (c)).
d) CONTROL A and CONTROL B connectors
•If you use YAESU FT-990 and/or FT-1000MP transceivers, please, follow instruction below.
NOTICE
Delivered control cables are directly suited for BAND DATA connectors of YAESU FT-990
and FT-1000MP transceivers.
Using an inappropriate cable may cause a serious damage to the ACOM 2S1 and your
transceivers (not covered under warranty)!
Figure 2-2 | Control cables YAESU FT-990 and FT-1000MP transceivers
Figure 2-2 | Control cables for YAESU FT-990 and FT-1000MP transceivers
NOTICE
Be extremely careful not to mix Aand Bcontrol and RF cable pairs. Damage to the
commutator and/or other equipment is possible, not covered by the warranty.

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
Page 16 of 32 | S e c t i o n INSTALLATION
June 2022
Connect both control cables (see Figure 2-2 | Control cables YAESU FT-990 and FT-1000MP transceivers) from
commutator's CONTROL A and CONTROL B connectors (see Figure 2-1 | Rear panel - Connections, Pos. (d)) to
the respective transceiver's A and B control (Band Data) connectors.
Table 2-1 | Control cable wiring for YAESU FT-990 and FT-1000MP transceivers
ACOM 2S1 commutator
Rear panel
Connecting cable
YAESU FT-990/FT-1000MP
transceivers / Rear panel
CONTROL A/B connectors
Band Data connector
MIC-type*
connector,
4-pin, male
(Rear panel
front view)
1 | +(11-14) VDC
MIC
connector,
4-pin,
female
(Solder view)
1
––––––––
1
Horseshoe DIN
connector,
8-pin,
male
(Solder view)
1 | +13.8 V (OUT)
Horseshoe
DIN-type
connector,
8-pin,
female
(Rear panel
front view)
2 | TX GND
2
––––––––
2
2 | TX GND (OUT)
3 | GND, Shield
3
––––––––
3
3 | GND
4 | TXINHIBIT
4
––––––––
8
4 | Band A (OUT)
Housing
-
Not connected
4
5 | Band B (OUT)
-
Not connected
5
6 | Band C (OUT)
-
Not connected
6
7 | Band D (OUT)
-
Not connected
7
8 | LINEAR
Housing
Cable shield
Housing
Housing
Table 2-1 | Control cable wiring for YAESU FT-990 and FT-1000MP transceivers
NOTICE
* Designation MIC-type is used for a circle 4-pin connector type and does not mean a
microphone!
Do not connect the control cable to the microphone input of your transceiver - this will
damage the transceiver!
•If any of your transceivers is different (nor YAESU FT-990, nor FT-1000MP), you'll need to
replace 8-pin, DIN connector on delivered control cable or to make a suitable adapter.
Please, see Table 2-2 | Signals and pin out of the CONTROL A/B connector and your transceiver's manual to
assemble the correct control cable according to the following instructions:
NOTICE
Using an inappropriate cable may cause a serious damage to the ACOM 2S1 and your
transceivers (not covered under warranty)!

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
June 2022
S e c t i o n INSTALLATION | Page 17 of 32
Table 2-2 | Signals and pin out of the CONTROL A/B connector
CONTROL A/B
connectors
Pin Nr.
Pin name
Description
Specification
MIC-type connector,
4-pin, male
(Rear panel.
front view)
1
+13 VDC
Power supply
+(11-14) VDC
2
TX GND
Ground on transmit
-
3
GND, Shield
Ground
-
4
TXINHIBIT
Disables transmission
-
Housing
-
Cable shield
Ground
Table 2-2 | Signals and pin out of the CONTROL A/B connector
1) Connect commutator's connector CONTROL, Pin 1 (+13V) to any DC supply voltage in the
range +(11-14) V available from the transceiver;
2) Connect commutator's connector CONTROL, Pin 2 (TX GND) to the transceiver's output
providing "ground on transmit" (it's usually dedicated for external amplifier T/R control).
Prefer an electronic output to a relay contact.
Transceiver producers give different names to this signal, for instance: TX-GND, SEND,
T/R-LINE, etc. Some transceivers require that "ground on transmit" is implemented via a
software command, or by changing the setting of a switch on the rear panel, or interior
of the transceiver.
Check your transceiver's manual or consult your dealer.
3) Connect commutator's connector CONTROL, Pin 3 (GND, Shield) to the common
transceiver's ground;
NOTICE
The connection cable must be shielded.
4) Connect commutator's connector CONTROL, Pin 4 (TXINHIBIT) to a dedicated transceiver's
input that disables transmission.
Transceiver producers give different names to this input and they are for instance
TX-INHIBIT, MUTE, LINEAR, ATU, etc.

User's Manual | ACOM 2S1 | Automatic XCVR Commutator
Page 18 of 32 | S e c t i o n INSTALLATION
June 2022
NOTICE
If your transceiver does not have TXINHIBIT input, it cannot be suited to the ACOM 2S1
XCVR commutator system (unless any modification is made inside the transceiver to get
such TXINHIBIT input).
Check your transceiver's manual or consult your dealer.
After successfully assembling of necessary control cables, you can connect them from commutator's
CONTROL A and CONTROL B connectors (see Figure 2-1 | Rear panel - Connections, Pos. (d)) to the respective
transceiver's A and B control (Band Data) connectors.
NOTICE
Be extremely careful not to mix Aand Bcontrol and RF cable pairs. Damage to the
commutator and/or other equipment is possible, not covered by the warranty.
e) KEY OUT and KEY IN connectors
Run a "daisy chain" wiring using Phono RCA connector terminated cables:
•From the commutator's KEY OUT connector (see Figure 2-1 | Rear panel - Connections, Pos. (e))
to the amplifier KEY-IN connector;
•From the amplifier KEY-OUT connector to the antenna selector (e.g., ACOM 2000S) KEY-IN
connector;
•From the antenna selector (e.g., ACOM 2000S) KEY-OUT connector to the KEY IN connector
(see Figure 2-1 | Rear panel - Connections, Pos. (e)) of the commutator.
If any of the units listed above (amplifier or antenna selector) is not present in the system, go to the next
unit. If no external apparatus is used, merely place a bridge between KEY OUT and KEY IN connectors of the
commutator.

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June 2022
S e c t i o n INITIAL CHECK AND OPERATION | Page 19 of 32
3. INITIAL CHECK AND OPERATION
NOTICE
Do not try transmitting until all the system is properly connected to the ACOM 2S1
commutator according to Section 2.3 Connections.
Figure 3-1 | Front panel - Indicators
Figure 3-1 | Front panel- Indicators
The operation of the commutator is fully automatic. But we recommend an initial check to be executed
before using it for the first time.
For the initial check, please, follow the sequence below:
1) Transceivers Power On
After following all instructions in Section 2.3 Connections, you can turn ON both transceivers. This will apply
DC voltage to the commutator. Powering sequence makes no difference. Both LED indicators Aand B(see
Figure 3-1 | Front panel - Indicators) on commutator's front panel must be OFF in RX mode. LED indicators A
or Blight only while the respective transceiver transmits: this indicates to the other transceiver's operator
that he cannot transmit at the same time.
2) Transceivers band set
Set different bands on both transceivers. Switch the antenna selector ON and the amplifier OFF (if any). Set
RF power controls of both transceivers to a possible minimum. Tune both transceivers to hear the typical
band noise.

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Page 20 of 32 | S e c t i o n INITIAL CHECK AND OPERATION
June 2022
3) Test transmission
Try a short transmission from transceiver A - its LED must light during transmission. Hold transceiver Ato
transmit and try simultaneous transmission from transceiver B: it must be disabled and LED Bmust rest
dark. The transceiver Bmust not be able to break transceiver Auntil you release A. When neither Anor B
transmits both transceivers must normally receive.
NOTICE
LEDs Aand Bshould never light simultaneously. Look for any connection error if you
note such condition (see Section 2.3 Connections).
4) Second test transmission
Try the same as described in Point 3 (above) but with Band Aexchanged.
5) Repeat instructions in Points 3 and 4 (above) at a low (5-10 Watts) output level
Try QSK CW from both transceivers: a first pressed KEY must "reject" CW dots and dashes of the second
one. The second transceiver must be automatically enabled when the first one returns to RX. Both
transceivers must be able to receive in the pauses of transmission.
6) Breaking the KEY IN / KEY OUT "daisy chain" wiring
Breaking the KEY IN / KEY OUT "daisy chain" wiring at any point must disable transmission of both
transceivers.
7) Breaking the KEY IN / KEY OUT "daisy chain" wiring
Restore all connections and turn ON the amplifier (if any). Try instructions in Point 5 again. The amplifier
must follow the frequency last transmitted by either transceiver. Increase the output to its nominal level -
no problems should be met.