ICS Linker IIa User manual

ICS
REPEATER
CONTROLLERS
LINKER IIa USER MANUAL
INTEGRATED CONTROL SYSTEMS
1076 North Juniper St.
Coquille, OR 97423
Email [e-mail]
Website www.ics-ctrl.com
Last updated 05/07/15
Linker IIa User Manual V1.20

1
TABLE OF CONTENTS PAGE NO.
Table of contents 1
General Description of the ICS Linker IIa Repeater Controller 2 - 3
Special features for the Linker IIa 4
Command Structure 5
Remote Base Controller 6 - 7
Quick connect for the control receiver 8
Quick connect for the repeater receiver 9
Specifications 10
Linker IIa board layout diagram 11
Jumper and Plug position diagram 12
Plug wiring diagrams 13
Function numerical list 14 - 16
Function descriptions 17 –70
Programmable tones 71
Repeater control codes table –use to record your DTMF codes 72
Linker IIa schematic diagram
Linker IIa User Manual version 1.19

2
General Description of the ICS Linker IIa Repeater Controller
Here at ICS we strive to make products that have new, innovative, easy to use features and excellent quality at a
reasonable cost. We believe the Linker IIa is such a product. The Linker IIa has such innovative features such as
remote base control, a full featured control receiver input (has priority), programming with actual values (i.e. Volts,
Hertz, Seconds, wpm) and a very easy to use 3 level command access feature which has over 65 commands
available. It also has microprocessor support for a CTCSS board, both encode and decode. There is a plug
specifically for the CTCSS board. The CTCSS encode also has an encode hang timer in which the time is
programmable. When designing the Linker IIa we worked hard to provide a product that is easy to use, durable and
of excellent quality at a reasonable cost.
The Linker IIa has many unique features. One such feature is the control receiver input. This input is unique in that
it provides a level of control normally only provided on more expensive controllers. It is optional to use the Control
receiver input as the repeater receiver input (port 1) and even the link / remote base receiver input (port 2) will
provide the access to control the repeater. The control receiver gives you control over the repeater even if the
repeater’s receiver is inaccessible. Also, with the addition of a resistor, you can pass the control receiver audio to
the repeaters transmitter audio output (port 1) and the audio level can be adjusted with the control receiver input
audio pot. The control receiver COS can be set to switch between 1 and 9 volts and the polarity can be easily set as
well. When the control receiver COS becomes active all the port 1 and Port 2 DTMF signals are ignored and the
Linker IIa only listens to the control receiver for DTMF codes. The repeater (Port 1) input has priority over the
remote base / link receiver (Port 2). This allows for priority control with the control receiver.
Another such unique feature is the remote base control system, which will allow you to use most radios that have
memories and that have a mike input for UP memory. You simply program in the frequencies, the offsets and the
CTCSS tones (encode and decode) into your radio’s memory and tell the Linker IIa how many memories you have
on your radio to increment through. The Linker IIa remembers which memory the remote base is set too even if the
power is turned off. All the user needs to do is select which memory he wants with a DTMF command. When the
remote base radio is disabled or turned off the Linker IIa will return the radio to the home memory. When desired
you may select from one of 6 link / remote base commands to control your link / remote base radio. These
commands are easy to use and give you an easy to use multi frequency remote base at a reasonable cost.
The new Linker IIa CTCSS control feature gives a wide range of control over CTCSS decode and encode signals.
The Linker IIa gives you DTMF on and off control over CTCSS decode, encode and the encode hang timer. Also
the CTCSS encode hang timer is programmable. The encode hang timer starts from the time the repeater receiver
becomes non-active. This will allow a reverse burst or courtesy tone to be heard after the receiver becomes inactive.
The ever growing set of easy to use features can be accessed by a secure Setup mode (program mode), a Control
operator mode and a User mode. If desired the Setup mode (program mode) can be accessed only by a hardware
jumper from the factory. A DTMF sequence (up to 10 digits) can be programmed to give access to the Setup mode
if desired. This provides the highest level of security. In the Setup mode (program mode) all the commands are
accessible by DTMF using their 2 or 3 digit command / function codes. This makes the controller programming
easy. The User and Control operator levels use from 1 to 5 digits to access these same functions if setup to do so.
From 0 to 25 DTMF codes can be setup for the User and Control operator levels allowing easy programming, total
flexibility and an extremely secure system for controlling the Linker IIa and its functions.
It can be difficult at times to work on a repeater without knowing what the incoming and outgoing signals are doing.
Connecting voltmeters, scopes and other monitoring equipment can sometimes be difficult. We have provided many
LEDs to help make the setup of the repeater easier. The Linker IIa has 9 of them. Most of the input and output
signals are indicated. The controller will also indicate when it recognizes a DTMF code. When not being used the
LEDs can be disabled with a jumper. We have found these indicators to be a big help when working with repeaters.

3
The control inputs and outputs of the Linker IIa repeater controller are very simple to use. There are 3 COS inputs,
2 CTCSS inputs and 4 open collector type outputs. The inputs include a Control receiver COS input, the repeater
input (port 1) with COS and CTCSS inputs, and the remote base / link receiver (port 2) also has a COS and a
CTCSS input. All of these COS and CTCSS inputs can be set to switch between 1 and 9 volts and the polarities are
programmable. Both ports 1 and 2 have COS and CTCSS inputs. You may select between the COS and CTCSS or
select both for ‘AND’ or ‘OR’ control. This allows for the switching back and forth between carrier squelch and
CTCSS (need an external CTCSS board (TS-64)) for the ‘receiver active’ signal.
The auxiliary outputs of the Linker IIa are multi featured and easy to use. The 3 auxiliary outputs can be used for
several different functions. All of the 3 auxiliary outputs can send a short pulse or either be locked on or off. The
Auxiliary 1 output has a programmable timer that can be enabled or disabled. It can also control a timed transmitter
fan. The Auxiliary 2 output optionally provides the PTT for the link / remote base transmitter (port 2). The
Auxiliary 3 output can provide control of the remote base memory selection. The 4th open collector output is for the
repeater / port 1 push to talk. All of the inputs are buffered and the outputs are protected to greatly reduce any
chance of damage.

4
SPECIAL FEATURES OF THE ICS LINKER IIa
CTCSS Encode / Decode Control
A very powerful feature of the Linker IIa is the support for the CSI TS-64 CTCSS encode / decode board for port 1.
Although this feature was designed with the CSI TS-64 board in mind it will work with many others as well. This
feature includes a separate plug to support the CSI TS-64 CTCSS board, CTCSS decode enable, CTCSS encode and
an encode hang timer for port 1. The CTCSS encode signal is mixed in with the repeater transmit audio. For more
information on this feature see the section on the CTCSS encode / decode control.
The Linker IIa gives you the option of having receiver 1 or receiver 2 (or both) enable transmitter 1 encode. The
Linker IIa has commands to enable and disable these functions. The commands are Enable RX 1 CTCSS encode
activate (function #110), Disable RX 1 CTCSS encode activate (function #111), Enable RX 1 CTCSS encode
activate (function #112), Disable RX 2 CTCSS encode activate (function #113).
Port 2 modes
Some other features special that the Linker IIa has are xpeat mode, slave repeater mode and full duplex mode on the
2ad port (Link / Remote base port). The xpeat is designed to activate transmitter 1 when receiver 2 becomes active
and transmitter 2 when receiver 1 is active. Receiver 1 will have priority.
The slave repeater mode on the ICS Linker IIa will allow two repeaters to be run on one controller. As the Linker
IIa has one IDer both repeaters will be IDed at the same time. The IDer will still try not to ID over any conversation
on either repeater.
The full duplex mode on the ICS Linker IIa allows full duplex operation on port 2. Both receivers and both
transmitters can be on at the same time and the audio from both receivers will be mixed together.
The Linker IIa now has a function to report what the remote base radio is set to (function #129). The controller will
report in morse code what memory the remote base is set to.
Beacon Mode
The Linker IIa now has Beacon mode. When the Linker IIa is in Beacon mode it will send the ID when the IDer
pending ID timer times out (see function #68). The polite ID timer will still operate holding off the ID until the
polite ID timer times out or until the receiver becomes nonactive.
Programmable Tones
Another new feature for the Linker IIa is programmable tones. There are currently 5 programmable tones
And 40 different tones available to put in the programmable tones. There are two new additional programmable
tones. The new tones are port 1 programmable tone when port 2 is active and change memory programmable tone.
Antikerchunker Filter
The Linker IIa's antikerchunker filter will help eliminate the kerchunking of your repeater. The operation is simple,
when the antikerchunker filter is enabled (see the Enable antikerchunker filter (command #118) and the Disable
antikerchunker filter (command #119) ) and Linker IIa sees that the repeater receiver is active the Linker IIa will
wait a programmed period of time (see the Set antikerchunker filter delay (command #120)) before it recognizes the
repeater receiver as active. If the repeater receiver stays active for the preprogrammed period of time the Linker IIa
will then recognize the repeater receiver as being active. Once the Linker IIa recognizes the repeater receiver is
active the Linker IIa will temporarily disable the antikerchunker filter for a preprogrammed period of time (see the
Set antikerchunker filter interval time (command #121).

5
COMMAND STRUCTURE
The command structure of the Linker IIa is easy to use and very versatile. It includes a Setup mode for
programming and 2 levels for control. The two levels are the Control operator mode and User mode. The structure
of these levels gives needed security and still provides a very easy system to setup and program. The Setup mode
gives you direct access to all the functions directly. In Setup mode the function codes are entered directly with your
DTMF pad. The Control op and User modes are very similar to each other. To access a command in either of these
modes you need to have programmed (from Setup mode) a DTMF sequence (1 to 5 DTMF digits) followed by the
function in a DTMF memory. When you enter the DTMF codes in Control op or User mode that are in a DTMF
memory the command in the DTMF memory will be called. A condition code can be added to the DTMF memory
to restrict that DTMF memory (and its command) to the Control op mode only, the command will then not be
accessible in the User mode.
The Setup mode (program mode) allows access to all the functions. All the functions can be activated just by
entering the 2 or 3 digit code for that function. When the Linker IIa controller leaves the factory the only way to
access the Setup mode is with the hardware jumper. It initially can not be accessed any other way. Normally if the
Setup mode jumper is in you are in Setup mode and if it is not in you are not in Setup mode. There are two
functions that can be used to enter and exit the Setup mode remotely, ‘Exit Setup mode’ (see function #59)and
‘Enter Setup mode’ (see function #58). The Setup mode can be accessed by putting the ‘Enter Setup mode’ function
in the Control op or User modes using a DTMF command memory (see function #78). The 1 to 5 digits you
program in will give you access to the Setup mode. If you only allow access to the DTMF code for the Setup mode
in Control op mode the Linker IIa can be setup to require up to 10 digits to access the Setup mode, 5 digits to go
from the User mode to the Control op mode and 5 digits to access the DTMF memory you programmed the “Enter
Setup” command into. Remote access to the Setup mode is only available if you make it so.
When the Linker IIa is in the Setup mode (program mode) the Linker IIa uses a special courtesy tone. The courtesy
tone is 3 dits or a Morse code “S” to indicate being in Setup mode. If the repeater is left in the Setup mode and the
repeater can not be physically accessed to remove the Setup jumper the Setup mode can be exited using the 2 digit
‘Exit Setup mode’ function. This is true even if the Setup jumper is still installed.
The Control op mode is intended to give access to control functions that only a few people should have. In the
Control op mode all the preprogrammed DTMF memories are available. In the User mode you can provide limited
access to the DTMF memories. Only the DTMF memories that have not been setup as Control op level, will be
accessible in User mode. Any, some or none of the Linker IIa’s commands can be enabled on this level. You
program any of the functions you want to give access to and on what level.
To give access to a function in the Control Operator or User modes a DTMF code and a function must be entered in
a DTMF memory. You must be in Setup mode to program a DTMF memory. To start the entry use the “ENTER
DTMF COMMAND LINE” function (#78). First you select a DTMF memory 0 – 24, then enter to 5 DTMF code
digits, then indicate if this DTMF memory is to be only available in the Control op level and of course the function
you wish to give access to (see the ENTER DTMF COMMAND LINE (#78) function in the function descriptions).
All 16 DTMF digits can be used in a DTMF code including A, B, C, D, * and #. An example of the DTMF code
layout for a few DTMF memories is shown below;
DTMF Memory number | DTMF codes, 1 to 5 digits | Control Op? | function
0 ` 2 # 0 N 33 (DISABLE TX 1)
1 2 # 1 Y 32 (ENABLE TX 1)
2 3 9 0 B # N 60 (SET CONTROL OPERATOR MODE)
3 C Y 61 (CLEAR CONTROL OPERATOR MODE)
4 A # 4 B 2 Y 58 (ENTER SETUP MODE)
5 B N 48 (ACTIVATE KEYPAD TEST)
Any of the functions can be used in a DTMF memory. There is a chart at the end of this manual that is similar to the
above and can be copied and used to keep track of your DTMF settings. Note: The Linker IIa controller comes with
all DTMF memories empty, you must use Setup mode (program mode) initially for access to the Linker IIa’s
functions.

6
LINKER IIa REMOTE BASE CONTROLLER
The remote base controller on the Linker IIa uses a new and unique method to control a remote base . Most radios
that have an up input on the microphone that can be used. The Linker IIa controller will allow you to select from
any one of the preset memories in the remote base radio’s memory. The Linker IIa supports from 1 to 250
memories. The Linker IIa remembers what memory the remote base radio is set to. The user only needs to select
which memory he wants to use and the Linker IIa will automatically select that memory on the remote base. This is
a very easy way of selecting remote base memories as the frequencies, offsets and CTCSS –DCS settings are all
preset in the remote base radio. You can choose to only have the receiver active, to have the receiver and transmitter
active or even only the transmitter active on the remote base radio. The commands are easy to setup and to use.
The connection from the remote base radio to the Linker IIa controller is straightforward. First you will need to
determine a way to get a COS signal from your remote base radio. The Linker IIa’s RX 2 COS input can read
voltages from 1 to 9 volts with a positive or negative polarity. While the RX 2 COS input will read from 1 to 9 volts
you can apply a voltage of 0 to 40 volts to it. The COS signal also needs to be able to operate with the Linker IIa’s
approximate input impedance of 100K. The Linker IIa’s COS inputs are preprogrammed to be positive acting and
the CTCSS inputs are also preprogrammed to be positive acting. The COS and CTCSS inputs will both switch at
about 2.5v from the factory. IF (and only if) you need to change the polarity or the switching voltages the Linker IIa
will allow you to do that without adding external circuitry. Please see the SET RX 1 VOLTAGE (Function #79 and
#80) for the repeater inputs (port 1) and the SET RX 2 COS VOLTAGE (Function #81 and #82) for the remote base
/ link (port 2) inputs. You might also want to look at the quick setup guide for the repeater receiver (see index).
The next connection that needs to be made is the remote base / link receiver (port 2) audio. This is fairly simple. If
you are using a regular radio (such as a mobile rig) as a remote base first you should use a resistor that has an
equivalent resistance with a sufficient power rating as the radio’s speaker, as this is the output impedance the radio’s
speaker output was designed for. This resistor should be tied from the audio output to ground. Keep the radio’s
volume as low as possible. You will not need much audio. The audio signal for the RX 2 input on the Linker IIa
can be taken from the signal or non ground side of this resistor. There are other ways to get an audio signal but his
is one easy way to get remote base / link audio. You may also use discriminator audio. The audio from the
discriminator can give you much better sounding audio.
The mike input of the remote base / link radio is the typical connection to the Linker IIa’s TX 2 audio. You may
want to add a resistor (typically 47k) in series with the mike input to match the low output impedance of the
Linker IIa’s RX 2 audio output to a high impedance microphone input of a remote base / link radio’s microphone
input.
If your radio has an “UP” input on its microphone input this can be used to give the Linker IIa control over which
memory to select. The auxiliary 3 output of the Linker IIa is used for this purpose. The “UP” input can be
connected directly to the auxiliary 3 input if the “UP” input is designed to go to ground for it’s activation. The
Linker IIa uses an open collector configuration for this function. If the “UP” input on the remote base radio does not
normally get switched to ground to select the next memory a relay may be connected to the auxiliary 3 output and
appropriate connections to the radio made on the other side of the relay. This is all that is necessary to wire up the
memory selection of your remote base.
The auxiliary 3 output has a programmable timer (see function #116) which times how fast the auxiliary 3 output
goes on and off. This timer can be set to speed up or slow down the rate in which the remote base memories are
selected.
The Linker IIa uses a “home memory” as a reference point. This is the memory in the remote base radio the
Linker IIa will consider memory number 0. The Linker IIa will always return the remote base radio to the home
memory when the remote base is disabled. Memory ‘0’ will always be the first memory to the Linker IIa. The
current memory number is stored in the Linker IIa’s EEPROM memory so the Linker IIa will remember the
currently selected memory the remote base is set to even if the power goes out.

7
The Linker IIa will always increment the remote base memory up, even when returning to the home memory or to
go to one memory below the current memory. The Linker IIa will “wrap around” memories. When the radio’s
highest memory is reached the Linker IIa will expect the next UP signal to bring the radio to the first or lowest
memory. While the memories are changing (or while any function is active) TX 1 will remain on. When TX 1
drops you will know the memory changing has been completed. The Linker IIa will send a cover tone while the
remote base memories are being selected.
Once all the connections are made and the COS input voltages (you probably don’t need to change these) are set you
will need to program the remote base radio itself. Once this is done the Linker IIa will need to know how many
memories it will have to increment through. This means the actual number of memories that show up on the display
of the remote base radio, even if they are not used. This is done using the “SET NUMBER OF REMOTE BASE
MEMORIES “ function (Function #71). The Linker IIa’s remote base memory numbers start at 0 so the first
memory is always memory number 0 (Home memory). Some radios start at memory 0 and some start at memory 1.
The number the Linker IIa needs programmed in for the number of memories it will have to increment through.
TX 2 will go off if any DTMF tones are recognized on any receiver input. When doing control functions in most
cases it is desirable to not be transmitting on the remote base’s transmitter as the remote base may be on a repeater’s
input or frequency that is being used by others.

8
QUICK CONNECT FOR THE CONTROL RECEIVER
NOTE: You do not need to use this input, it is optional, it is only for use with a separate control receiver. If you
do not plan to use a separate control receiver then please skip this page. The repeater receiver port has access to
all the same control functions (the control receiver has priority). Do not connect the repeater receiver to this
input.
1. If you decide to use a control receiver you should have the control receiver COS and audio signal already
wired to the proper connections according to the plug layout in this manual before you start. These signals
should be suitable to drive a 100K ohm load. It is not necessary to use a control receiver to operate the
Linker IIa repeater controller.
2. Make sure the repeater’s transmitter is disconnected or disabled
3. Check to see what the COS on and off voltages are and write them down. The difference between them should
be at least 1V and can be somewhat less if the COS voltages are very stable. If a battery is being used to power
the Linker IIa or the receiver, the COS voltages that occur during battery discharge should also be taken into
consideration. In the case of a discharging battery the voltage output from R16 will eventually change as the
battery voltage goes below 10vdc.
4. Turn the power off. The control receiver audio input amplifier jumper JP2 setting needs to be determined. For
high gain (about 10 times) do not install the jumper. For a low / normal gain ( about 2 times ) jump
pins 2 & 3. To de-emphasize the audio (discriminator audio) jump pins 1 & 2.
5. If the COS goes positive when activated make sure the jumpers in JP5 have their skinny parts both faced
towards U2. This is the position for a positive going COS polarity. From the factory the jumpers are set for a
positive polarity (NOTE: Turn the jumpers in JP5 90 degrees for the opposite COS polarity)
6. If your COS is negative acting make sure the jumpers in JP5 are set so that one jumper has its long side facing
U2. This is the jumper position for a negative going COS polarity.
7. If the Linker IIa’s control receiver COS input is setup for a positive COS monitor the voltage on pin 12 of U2, if
the Linker IIa’s control receiver is setup for a negative COS monitor the voltage on pin 13 of U2
8. Adjust R54 (CONTROL RX COS LEVEL POT) until the voltage reading is in the middle of the measured COS
voltage from step 3.
9. If you have a scope available, monitor the signal on U2 pin 7, if not skip to step 11.
10. Send a DTMF digit through the control receiver. Set R16 (CONTROL RX AUDIO) until you get about a
200mV reading. You should now see the VALID DTMF LED steadily lit up (no flickering).
11. If you do not have a scope available start by sending a DTMF digit tone through the control receiver.
12. Adjust R16 (CONTROL RX AUDIO) until you see the VALID DTMF LED light up. Try to find a center point
so you are not on the edge of operation.
13. The control receiver should now be ready to perform control functions

9
QUICK CONNECT FOR THE REPEATER RECEIVER
This is a procedure that will help connect up the repeater’s receiver. It is not the only way to do it but one that we
have used that works well.
1. You should have a repeater receiver COS and audio signal already wired to the proper connections according to
the plug layout in this manual before you start. These signals should be suitable to drive a 100K ohm load. The
input amplifier jumper JP7 setting needs to be determined. For high gain (about 10 times) do not install the
jumper. For a low gain ( about 2 times ) jumper pins 2 & 3. To de-emphasize the audio (for discriminator
audio) jump pins 1 & 2.
2. The default trigger voltages for RX 1 and RX 2 are 2.4v off and 2.5V on. This results in a positive acting COS
These voltages can be reprogrammed if your COS signals are negative acting or need a different trigger point.
If you have a positive acting COS and 2.5v is a good trigger point then please skip to step 11.
3. Make sure the repeater’s transmitter is disconnected or disabled
4. Check to see what the COS on and off voltages are and write them down. The difference between them should
be 1V or so but can be somewhat less if the COS voltages are very stable. If a battery is being used the COS
voltages during battery discharge should also be taken into consideration when programming these settings.
Write down the COS off voltage and the COS on voltage on a piece of paper.
5. Make sure the Linker IIa is in Setup mode (install the setup jumper JP4) and the following DTMF codes could
be sent from the control receiver or you can use a jumper to +12v to activate the port 1 COS input. If you use a
jumper then you would connect the 12v for ‘COS active’ and disconnect it for ‘COS not active’ when the COS
input is set to factory default voltages.
6. You will need to enter in two voltage values that are in-between the two measured voltages in step 4. You may
use three digits and the * as a decimal point. You would enter 2.34 Volts as 2*34 on your DTMF keypad.
7. For the repeater’s (RX 1) COS on level setting activate the function SET RX 1 COS VOLTAGE ON LEVEL.
Enter in a value that is at least 0.5v away from the measured COS off voltage. This voltage should be
in-between the measured ON and OFF receiver COS voltages.
8. After completing the SET RX 1 COS VOLTAGE ON LEVEL function you may need to enter a second voltage
value for the COS off setting. To set the repeater’s COS off setting use the function SET RX 1 COS
VOLTAGE OFF LEVEL and enter in a value at least 0.2v away from the measured COS on voltage. This
voltage should be in-between the measured ON and OFF COS voltages.
9. Care should be taken when adjusting the repeaters audio in level with R66 (RX 1 AUDIO) so the DTMF
decoder gets a signal which will allow a reliable decoding of any DTMF digits from the repeater’s receiver
10. The repeater receiver COS and CTCSS input (Port 1) and the remote base / link (Port 2) COS and CTCSS
inputs are set up in the same general way and this quick connect procedure can be used to setup the remote base
/ link COS and CTCSS inputs. The Port 2 COS and CTCSS
11. If you do not have a scope available start by sending a DTMF digit tone through the control receiver.
12. Adjust R66 (RX1 AUDIO LEVEL) until you see the VALID DTMF LED light up. Try to find a center point so
you are not on the edge of operation.
13. The control receiver should now be ready to perform control functions

10
SPECIFICATIONS
SUPPLY VOLTAGE 13.8V
IDLE CURRENT @13.8V 29mA LEDs disabled
MAXIMUM CURRENT TX 1 OUTPUT 1 A
MAXIMUM CURRENT ON AUXILIARY 1 OUTPUT 1 A
MAXIMUM CURRENT ON AUXILIARY 2 OUTPUT 1 A
MAXIMUM CURRENT ON AUXILIARY 3 OUTPUT 1 A
VOLTAGE IN ON RECEIVER 1 AUDIO INPUT 20mVpp to 10Vpp
VOLTAGE IN ON RECEIVER 1 AUDIO INPUT 20mVpp to 9Vpp
VOLTAGE IN ON RECEIVER 2 AUDIO INPUT 20mVpp to 9Vpp
VOLTAGE IN ON THE CONTROL RECEIVER AUDIO INPUT 20mVpp to 9Vpp
MAX VOLTAGE OUT ON RECEIVER 1 AUDIO OUTPUT 9Vpp
MAX VOLTAGE OUT ON RECEIVER 2 AUDIO OUTPUT 9Vpp
VOLTAGE IN ON THE RX 1 COS 0 to 30V 1 to 9V readable
VOLTAGE IN ON THE RX 2 COS 0 to 30V 1 to 9V readable
VOLTAGE IN ON THE CONTROL RX COS 0 to 30V 1 to 9V readable
VOLTAGE IN ON THE RX 1 CTCSS 0 to 30V 1 to 9V readable
VOLTAGE IN ON THE RX 2 CTCSS 0 to 30V 1 to 9V readable
OUTPUT IMPEDANCE FOR TRANSMITTER 1 AUDIO OUTPUT < 300 ohms
OUTPUT IMPEDANCE FOR TRANSMITTER 2 AUDIO OUTPUT < 300 ohms
INPUT IMPEDANCE ON RECEIVER 1 AUDIO INPUT ~100K ohms
INPUT IMPEDANCE ON RECEIVER 2 AUDIO INPUT ~100K ohms

11

12
J1 12V Power in, Center Positive, 2.5mm coaxial type jack
J2 Control receiver COS and audio in
J3 RX 1 CTCSS port, connections for 3rd party CTCSS board
J4 RX 1 connection for ICS DADM board
J5 RX 2 connection for ICS DADM board
JP 1 LED ground - Remove this jumper to disable LED's
JP 2 Control RX audio - 1 & 2 de-emphasized, 2 & 3 low gain (~2X ), no jumper high gain (~10X )
JP 3 RX 1 CTCSS Decode enable - Install jumper to enable 3rd party decoder
JP 4 Setup mode jumper - install to put the controller in setup mode
JP 5 Control RX COS polarity - Rotate both jumpers 90 degrees for opposite COS polarity
JP 6 TX 2 tone enable - Enables courtesy tones and ID on TX 2 (Only for Slave repeater mode)
JP 7 RX 1 audio - 1 & 2 de-emphasized, 2 & 3 low gain (~2X ), no jumper high gain (~10X )
JP 8 RX 2 audio - 1 & 2 de-emphasized, 2 & 3 low gain (~2X ), no jumper high gain (~10X )
P1 Connector for Port 1 connections
P2 Connector for Port 2 connections
JP 1
JP 2JP 3
JP 4 JP 5
JP 6
JP 7
JP 8
J1
P2
PORT 2
POWER
CONTROL RX
J2
P1
PORT 1
J3
CTCSS
DECODE EN CNTL AU
SETUP CNTL RX COS
POLARITY
LED GROUND
RX 1 AUDIO
RX 2 AUDIO
J4J5 RX 1 DADMRX 2 DADM
1
1
11 1 1

13
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
V+ OUT 100ma (0.1a) MAX
GND
GND
GND
TX 1 PTT OUTPUT (OPEN COLLECTOR)
CTCSS ENCODE ENABLE
AUX 1 / FAN / TIMED OUTPUT (OPEN COLLECTOR)
CTCSS TX 1 TONE
RX 1 DISCRIMINATOR AUDIO
AUX 2 / TX 2 PTT OUTPUT (OPEN COLLECTOR)
AUX 3 / MEMORY SELECT (OPEN COLLECTOR)
RX 1 COS INPUT
TX 2 AUDIO OUTPUT
RX 1 FILTERED AUDIO
RX 2 COS INPUT
RX 1 AUDIO IN
CONNECTORS ON LINKER IIa BOARD
TX 1 AUDIO OUTPUT
NC
RX 1 CTCSS INPUT
V+ OUT 100ma (0.1a) MAX
RX 1 AUDIO INPUT
RX 2 AUDIO INPUT
NC
RX 2 CTCSS INPUT
CTCSS DECODE SIGNAL
GND
2. CONTROL RX AUDIO INPUT
V+ OUT 100ma (0.1a) MAX
V+ OUT 100ma (0.1a) MAX
3. GND
1. CONTROL RX COS INPUT
P1
PORT 1
PORT 2
P2
J3 CTCSS PORT
1
2
3
4
AUDIO IN
AUDIO OUT
GND
+10V
J4
J5
AND
RX 1 AUDIO
RX 2 AUDIO
JUMP PINS 1 & 2 IF ICS DADM NOT USED
DO NOT USE +10V EXTERNALLY
CONTROLLER DAMAGE MAY OCCUR
1 2 3
J2
CONTROL RX INPUT
SHOWN IS THE JACK WHICH IS
PLUGGED INTO THE LINKER IIa BOARD
1
2
3
4
5
6
7
8
9
10

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COMMAND / FUNCTION LIST FOR THE ICS LINKER IIa CONTROLLER
1. Transmitter enable / disable commands
Enable TX 1 32
Disable TX 1 33
Force TX 1 on 85
Force TX 1 on clear 86
Enable TX 2 52
Disable TX 2 51
2. Receiver enable / disable commands
Use only RX 1 COS input 35
Use only RX 1 CTCSS input 36
AND RX 1 COS and CTCSS inputs 93
RX 2 enable 50
RX 2 and TX 2 disable 49
Use only RX 2 COS input 96
Use only RX 2 CTCSS input 97
AND RX 2 COS and CTCSS inputs 98
3. Auxiliary output commands
Turn auxiliary output 1 off 39
Turn auxiliary output 1 on 40
Turn auxiliary output 2 off 41
Turn auxiliary output 2 on 42
Turn auxiliary output 3 off 43
Turn auxiliary output 3 on 44
Pulse auxiliary 1 output 45
Pulse auxiliary 2 output 46
Pulse auxiliary 3 output 47
Set auxiliary 1 output timeout time 69
Turn auxiliary timer off 37
Turn auxiliary timer on 38
Enable timed TX fan on auxiliary 1 output 88
Disable timed TX fan on auxiliary 1 output 89
Set auxiliary 3 pulse time (pulse duration) 116
4. IDer commands / settings
Force ID 34
Enable IDer 62
Disable IDer 63
Set IDer polite ID time 67
Set IDer pending 68
Set word per minute rate 70
Enter new ID 76
Activate Beacon mode 114
Deactivate Beacon mode 115
ID cancel enable 134
ID cancel disable 135
TX2 ID with TX1 enable 136
TX2 ID with TX1 disable 137

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5. DTMF command setup commands
Enter new DTMF command line 78
Clear all DTMF command lines 74
Clear one DTMF command line 75
Turn DTMF muting on 91
Turn DTMF muting off 92
Set RX2 DTMF control 99
6. Tone control
Courtesy tone enable 56
Courtesy tone disable 57
Turn on test tone 64
Turn off test tone 65
Set new cw frequency 77
Set prebeep time 122
Change a programmable tone 127
Play a tone 128
Set courtesy tone speed 133
7. System control functions
Warm reset 55
Enter setup mode 58
Exit setup mode 59
Set control operator mode 60
Clear control operator mode 61
Set parameters to factory default 66
Save statuses 87
Keypad test 48
Enable antikerchunker filter RX 1 118
Disable antikerchunker filter RX 1 119
Enable antikerchunker filter RX 2 138
Disable antikerchunker filter RX 2 139
Set antikerchunker filter delay 120
Set antikerchunker filter interval time 121
Program terminator digit 131
Terminator control 132
8. Transmitter settings
Set hang time 72
Set TX 1 timeout time 73
Set TX 2 timeout time 109
9. Receiver settings
Set RX 1 COS voltage off level 79
Set RX 1 COS voltage on level 80
Set RX 1 CTCSS input voltage off level 83
Set RX 1 CTCSS input voltage on level 84
Set RX 2 COS voltage off level 81
Set RX 2 COS voltage on level 82
Set RX2 CTCSS off level 94
Set RX2 CTCSS on level 95
Set RX2 DTMF control 99

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10. Remote base / Link commands
RX 2 and TX 2 disable 49
Disable TX 2 51
Enable TX 2 52
RX 2 enable 50
RX 2 enable w/memory select 53
RX 2 & TX 2 enable 117
RX 2 & TX 2 enable w/memory select 54
Set number of remote base memories 71
Set remote base home memory 90
Activate xpeat 105
Set port 2 to half duplex 106
Set port 2 to full duplex 107
Set port 2 to slave repeater 108
Report the current remote base memory number 129
Set memory report after memory select 130
11. Commands for TX 1 CTCSS encode (Linker IIa only)
Activate CTCSS encode hang timer 100
Deactivate CTCSS encode hang timer 101
Set CTCSS encode hang timer time 102
Activate CTCSS encode 103
Deactivate CTCSS encode 104
Enable RX 1 CTCSS encode activate 110
Disable RX 1 CTCSS encode activate 111
Enable RX 2 CTCSS encode activate 112
Disable RX 2 CTCSS encode activate 113
Force CTCSS encode on 125
Cancel CTCSS encode on 126

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Definition of Terms used
1. Key up –To activate the Control or Repeaters receiver COS (The repeaters receiver needs to be allowed to do
DTMF control)
2. Unkey –To deactivate The Control or Repeaters receiver COS
3. COMMAND ACCEPTED indication –The controller sends a CW letter “K” for “OK”
4. ENTER NEXT DATA code –The controller sends a CW letter “M” for “ready for MORE information”
5. TX 1 = Transmitter 1 (typically the repeaters transmitter)
6. TX 2 = Transmitter 2 (typically the remote base / link transmitter)
7. RX 1 = Receiver 1 (typically the repeaters receiver)
8. RX 2 = Receiver 2 (typically the remote base / link receiver)
9. FUNCTION = “command / function” as described in the previous text
10. A decimal point can be entered on some functions by using the ‘*’ key on your touch pad
FUNCTION: ENABLE TX 1
FUNCTION CODE: 32
PURPOSE: Enables the TX 1 output
HOW TO USE:
1. Key up
2. Enter the ENABLE TX 1 function code.
3. Unkey
4. The controller sends the COMMAND ACCEPTED indication
5. The TX 1 output is now enabled.
The ENABLE TX 1 command will enable TX 1. If TX 1 was disabled on power up TX 1 will again be disabled on
power up (or warm reset) unless you use SAVE STATUSES (Function number 87). If you ENABLE TX 1 and then
use the SAVE STATUSES function TX 1 will always be enabled when a power or warm reset occurs.

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FUNCTION: DISABLE TX 1
FUNCTION CODE: 33
PURPOSE: Disables the TX 1 output
HOW TO USE:
1. Key up
2. Enter the DISABLE TX 1 function code
3. Unkey
4. The controller sends the COMMAND ACCEPTED indication
5. The TX 1 output is disabled.
The DISABLE TX 1 command will disable TX 1. If TX 1 was enabled on power up TX 1 will again be enabled on
power up (or warm reset) unless you use SAVE STATUSES (Function number 87). If you DISABLE TX 1 and then
use the SAVE STATUSES function TX 1 will always be disabled when a power or warm reset occurs.
FUNCTION: FORCE ID
FUNCTION CODE: 34
PURPOSE: To force the controller to send the CW ID
HOW TO USE:
1. Key up
2. Enter FORCE ID function code
3. Unkey
4. When the command is accepted the controller will send the preprogrammed CW ID.
When the controller sends a forced ID the ID interval timer is not reset.

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FUNCTION: USE ONLY RX 1 COS INPUT
FUNCTION CODE: 35
PURPOSE: Changes the receiver 1 input to use the RX 1 COS input only
HOW TO USE:
1. Key up
2. Enter USE ONLY RX 1 COS INPUT function code
3. Unkey
4. The controller sends the COMMAND ACCEPTED indication
5. Receiver 1 will now only use the receiver 1 COS input
This function switches control for RX 1 only to the RX 1 COS input for receiver 1.
FUNCTION: USE ONLY RX 1 CTCSS INPUT
FUNCTION CODE: 36
PURPOSE: Changes the receiver 1 input to use the RX 1 CTCSS input only
HOW TO USE:
1. Key up
2. Enter USE ONLY RX 1 CTCSS INPUT function code
3. Unkey
4. The controller sends the COMMAND ACCEPTED indication
5. Now only the RX 1 CTCSS input will activate RX 1.
This function switches control for RX 1 to only the RX 1 CTCSS input