S-COM S-COM 6K User manual

S-COM 6K
MICROPROCESSOR REPEATER CONTROLLER
OWNER'S MANUAL
V1.02 03-16-91
(V2.0 & V2.01 upgrades in back)
Rev. 04-10-2021
S-COM, LLC
P.O. Box 1546
LaPorte, CO 80535-1546
U.S.A.
970-416-6505
www.scomcontrollers.com

6K V1.02 03-16-91 1
IMPORTANT!
1. This product uses CMOS integrated circuits and other components that can be damaged by
static electricity. Be sure that you are properly and safely grounded, and are working at a
static-free workstation, when handling these components.
2. This product uses a lithium battery to provide power to the memory system when main
power is interrupted. This lithium battery is a primary cell. Do not attempt to recharge it!
3. The pin designations of the DB25 connector in the 6K are slightly different than the pin
designations of the DB25 connector in the 5K. Specifically, pins 16 and 18 are active
signals in the 6K; these pins are connected to ground in the 5K. Be sure you have checked
your cable and removed connections from pins 16 and 18 if you are replacing a 5K
controller with a 6K controller!

6K V1.02 03-16-91 2
DESCRIPTION
1. INTRODUCTION
The S-COM 6K is a high-quality, compact, microprocessor-based repeater controller
intended for use in amateur radio and commercial radio installations. Incorporating
advanced hardware and software designs, the 6K provides most-often-needed control
functions and powerful new features not found in any comparable-cost controller.
The 6K is fully remotely programmable with DTMF commands via the telephone or via the
receiver ports, thus eliminating the inconvenience of returning EPROMs, microcontroller ICs,
and PC boards to the factory for reprogramming. No jumpers or diodes are needed for
programming. Data is retained in non-volatile memory, ensuring that no information is lost
during power outages . . . making extra trips to the repeater site unnecessary.
2. STANDARD FEATURES
A. HARDWARE
a. Configuration
The standard 6K controller package consists of a Main Board and a Telephone Interface
Module mounted in a rackmount cabinet. A set of mating connectors and a manual
complete the basic package.
b. Cabinet
The cabinet provides mounting for the Main Board, the Telephone Interface Module Board,
and up to two optional Audio Delay Module Boards. The cabinet can be installed in a
standard 19" wide equipment rack. The cabinet is constructed from three basic parts: An
Iridite-plated chassis box, an Iridite-plated chassis cover, and a black anodized front panel.
The cabinet occupies 1-3/4" of vertical rack height, and measures about 7" deep. This
shallow cabinet may be installed in any rack, including the slim Motorola rack cabinets.
c. Main Board
The 6K Main Board measures 6"deep by 8" wide, and can operate as a stand-alone
controller. The digital portion of the board contains the microprocessor, memory, and logic
input/output circuits. The analog portion contains the DTMF encoder/decoder, audio
crosspoint switch, tone synthesis, and audio interface circuits. Two connectors, a DB25
female and a 2.5 mm DC power jack, are mounted on the Main Board. These connectors
protrude through cutouts in the rear of the cabinet, allowing the interior of the cabinet to be
free of wiring harnesses.
d. Telephone Interface Module
The Telephone Interface Module (TIM) is constructed on a 3" by 6" PC board, and adds
Autopatch, Reverse Patch, and Phone Line Control capabilities to the 6K Main Board. It is
registered with the FCC under Part 68 Rules, eliminating the need for a separate telephone

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coupler. Transient protection and RFI filtering is provided. The all solid-state design of the
TIM eliminates the possibility of mechanical relay failure, and the built-in electronic hybrid
allows both half-duplex and full-duplex autopatch calls. The TIM supports both regenerated
DTMF dialing and 10/20 PPS rotary dialing.
B. SOFTWARE
a. CW Identifier
The software CW Identifier stores remotely-programmable multiple call signs with ID Tail
Messages. The interval between identifications is also programmable. The CW is internally
mixed with repeat audio. The ID'er is "polite," which means that it attempts to identify only
during breaks between transmissions.
b. CW Messages and Paging Formats
Most of the CW messages are remotely programmable. CW pitch and speed is
programmable, and can even be changed within a message. The CW character set
includes alphanumerics, punctuation, and a large library of "beeps." The CW amplitude
level is set with a potentiometer.
The 6K supports single-tone (group call), two-tone sequential, 5/6-tone, and DTMF paging
formats. Separate pots allow adjustment of tone paging and DTMF paging. Pages may be
stacked for convenient call-ups of ARES members, weather spotters, DX Club members,
on-the-airmeetings, and so on.
c. Timers
All timers in the 6K are derived from the microprocessor's crystal-controlled clock circuit for
improved accuracy over other methods. Most timers are remotely programmable, including
the Courtesy Timer, Dropout Timer, Timeout timer, Autopatch Timer, etc.
d. Repeater Characteristics
The character of a repeater can be varied by choosing distinctive Courtesy Messages,
Timeout Messages, Dropout Messages, and their associated timers. The repeater can be
placed into one of several access modes, or disabled. These characteristics can be
changed by command or by a transition detected by one of the logic inputs.
e. Clock and Calendar
A CW readout of the current time and date can be commanded. The clock can be read in
either 12-hour or 24-hour format. An additional command is used to adjust the accuracy of
the clock. (Power must be provided continuously to the controller for the clock and calendar
to stay set).
f. Logic Inputs and Outputs
Logic inputs are used to detect a change of state in monitored devices at the repeater site.
Logic outputs can be manipulated by command to pulse, or latch, a controlled device at the

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site.
g. Command Language
Commands are given to the 6K with an easy-to-use DTMF language. Security is enhanced
with a password system, as well as programmable restrictions on DTMF decode operation.
A library of macros may be defined for the repeater's users. Macros may be created,
deleted, renamed, and modified at any time by authorized control operators.
3. OPTIONAL FEATURES
Audio Delay Module
The Audio Delay Module (model ADM/K) is constructed on a 2.1" by 2.7" PC board. It
removes squelch noise bursts and DTMF tone bursts from received audio. Up to two ADMs
may be installed in the 6K cabinet, one each for receiver #1 and receiver #2. The ADM will
delay audio in the range of 50 ms to 150 ms, adjustable via a potentiometer.

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LIMITED WARRANTY
This warranty gives you specific legal rights, and you may also have other rights which vary from
state to state.
COVERAGE
Except as specified below, this warranty covers all defects in material and workmanship in this
product. The following are not covered by the warranty:
1. Damage to, or deterioration of, the external cabinet.
2. Damage resulting from lightning, accident, misuse, abuse, or neglect.
3. Damage resulting from failure to follow instructions contained in your owner's
manual.
4. Damage occurring during shipment of the product (claims must be presented to the
carriers).
5. Damage resulting from repair or attempted repair by anyone other than S-COM
Industries.
6. Damage resulting from causes other than product defects, including lack of
technical skill, competence, or experience of the user.
7. Damage to any unit which has been altered or on which the serial number has been
defaced, modified or removed.
ENFORCEMENT
This warranty may be enforced only by the original purchaser.
LENGTH OF WARRANTY
For both labor and parts, this warranty will be effective for one (1) year from the date of original
purchase.
WHAT WE WILL PAY FOR
We will pay all labor and material expenses for items covered by the warranty. Payment of
shipping charges is discussed in the next section of the warranty.
HOW YOU CAN GET WARRANTY SERVICE
Your unit must be serviced by S-COM's Service Department. Please do not return your unit to
the factory without prior authorization. You must pay any shipping charges if it is necessary to
ship the product to service. However, if the necessary repairs are covered by the warranty, we will
pay the return shipping charges to any destination within the U.S. Whenever warranty service is

6K V1.02 03-16-91 6
required, you must present the original dated invoice or a photocopy.
S-COM's liability for any defective products is limited to repair or replacement of the product, at S-
COM's option.
S-COM reserves the right to make any changes in design or additions to, or improvements in, its
products without any obligation to install such additions or improvements in equipment previously
sold. S-COMfurtherreserves the right to replace defective parts under warranty with different or
improved parts.
This warranty is expressly in lieu of all other warranties, expressed or implied, including any implied
warranty of merchantability or fitness, and of all other obligations of liabilities on the part of S-COM.

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THEORY OF OPERATION
1. INTRODUCTION
Great care was taken in the design of your controller to make it "installer-friendly." Audio and logical
interfaces were made as universal in nature as possible, so that a minimum of external hardware is
needed to complete the installation. Although the controller's "engine" is a powerful
microprocessor, the command language is designed to be easy-to-learn and flexible.
2. PRE-PROGRAMMING (DEFAULTS)
The controller needs to know your repeater's call sign for its identifier; you must also tell it your
choice of courtesy message, timeout timer, and so on.
You can program the controlleron your workbench with an external DTMF pad and other devices to
simulate the repeater. Or, you can install the controller in your repeater and program it through one
of the receivers, or the phone line.
To make the installation easier, the controller comes "pre-programmed" with certain default
information stored in its non-volatile memory. When you have finished the installation, you may
overwrite this default information by entering DTMF commands. If it ever becomes necessary to
force the controller into its original default condition again, you can accomplish this by using the
initialize pushbutton and a power-up sequence (the procedure is explained later). This procedure
causes the microprocessor to read default information from the EPROMand write it over the old
information stored in the non-volatile memory.
3. POWER REQUIREMENTS
Your controller has only a modest power requirement, which can be supplied by the repeater's own
12 V power supply in most cases.
The controller's Main Board and Telephone Interface Module together require 12 V to 15 V DC at
less than 100 mA. (Do not exceed 15 V ordamage may occur). The controller does not require
regulated power, since it contains internal voltage regulators to create the necessary 10 V audio
supply and the 5 V digital supply. A third supply of 4.5 V is created from the 10 V audio supply, and
is used as the audio section's bias voltage.
4. REPEATER INTERFACING
Besides the power supply, the controller requires a minimum of four connections to the repeater.
They are: (1) Receiver COR; (2) Receiver Audio; (3) Transmitter PTT; and (4) Transmitter Audio.
You must eliminate any paths that might bypass the controller. In other words, there must not be
any connection from receiver audio to transmitter audio or from receiver COR to transmitter PTT
except through the controller. Otherwise, the controller will not be able to fully take charge of
repeater control functions.
If you require subaudible tone operation, you may connect a CTCSS decoder's output to the
controller. The controller will then allow you to switch the repeater from carrier operation to one of

6K V1.02 03-16-91 8
several CTCSS modes via DTMF commands.
5. 2nd RECEIVER INTERFACING
An additional receiver can be interfaced to your controller, which can act as either a link receiver or
a control receiver. If a 2nd receiver is used, the controller requires a minimum of two additional
connections. They are: (1) Receiver COR; and (2) Receiver Audio.
If you require subaudible tone operation for the 2nd receiver, you may connect a CTCSS decoder's
output to the proper input on the controller.
NOTE: The two Receiver COR inputs, the two CTCSS Decoder inputs, and the Transmitter PTT
output each has an associated dip switch on the Main Board. These switches are used to invert, or
not invert, the appropriate signal. This means that the controller can accommodate either low-
active or high-active signals.
6. EXTERNAL DEVICE INTERFACING
The controller has three Logic Inputs, each of which can monitor the state (ON or OFF) of an
external device at the repeater site. Since you can program the controller to detect either a low-to-
high transition or a high-to-low transition (or both), there is no need for the above-mentioned "invert"
switches on these inputs.
You can monitor such sensors as power failure, a high-temperature detector, a high-water detector,
or an intrusion alarm.
The controller also has three Logic Outputs, each of which can control (ON or OFF) an external
device at the repeater site. Power MOSFETs are used as the switching devices, which are
connected in an open-drain configuration (similar to transistors wired in an open-collector
configuration).
Each output can sink 75 mA when ON and withstand 40 V when OFF. All three outputs are
protected from transient damage.
7. AUDIO GATING
The controller uses an 8 x 12 analog crosspoint switch IC for audio gating. This IC operates under
instructions from the microprocessor. Since all audio sources (receivers, tone generators, and the
landline) are fed into the crosspoint switch, and since all audio loads (transmitter, tone decoder, and
landline) are driven from the crosspoint switch, the controller's audio control flexibility far exceeds
simpler designs.
8. TONE GENERATION
CW and paging tones are generated as square waves by the HD6340 Programmable Timer IC.
These square waves are shaped by a transconductance amp stage to reduce the "thumping"
characteristic heard on CW messages. (This thumping effect is caused by the DC component in
the square wave pulse train). The tone is then filtered by a 6th-order, switched-capacitor lowpass
stage to yield sine waves. The filter is under microprocessorcontrol and tracks the tone frequency.
The result is a constant-amplitude sine wave tone that can be programmed to any desired

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frequency in the range of 100 Hz to 3000 Hz, with an accuracy of a few Hertz. CW amplitude and
paging amplitude are separately adjustable with pots.
DTMF characters are generated via the encoder portion of the MT8880 DTMF Transceiver IC.
DTMF paging amplitude is pot-adjustable. DTMF dialing amplitude is not adjustable, and is fixed at
the level set by FCC Part 68 regulations.
9. MEMORY PROTECTION
The controller contains circuitry to protect the data stored in RAM and maintain the data during
power outages. A DS1210 IC monitors the 5 V logic supply; when it detects an out-of-tolerance
condition, the IC disables the RAM's chip-enable input. It switches the RAM's Vcc input from the
logic supply to the lithium battery when the logic supply falls too low to maintain data integrity. The
lithium battery has a lifetime of over 5 years (10 years if kept at room temperature), since the
amount of current drawn by the RAM is very low under backup conditions (a few microamperes).
10. VOLTAGE MONITOR AND WATCHDOG TIMER
The controller contains circuitry to properly start the microprocessor when power is applied, to stop
the microprocessor when power fails, and to restart the microprocessor if it gets into a runaway
condition from a spike or transient.
A DS1232 IC monitors the 5 V logic supply and asserts the microprocessor's reset input when the
supply is out of tolerance. This method is superior to simple RC reset circuits, which may not
properly reset the CPU after voltage sags (brown-outs). The reset signal that is generated by the
DS1232 drives not only the microprocessor but also other ICs to ensure that the controlled loads
will be turned off, and that a graceful power-down sequence will be observed.
The DS1232 also monitors a software-generated "watchdog" signal. This signal is created at
intervals by the execution of the microprocessor's software program. If the CPU fails to execute the
program correctly, the watchdog signal will not be generated. The DS1232 will time out in less than
one second if it does not receive the watchdog signal, and it will force the microprocessor to restart
the program.