Back to Home   Technical Information on S‑COM Repeater Controllers    

Compiled by Mike Morris WA6ILQ
Maintained by Robert Meister WA1MIK


Click here or on the logo above to go to the S-COM factory website

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The contents of this page, like most here at www.repeater-builder.com, are totally dependent on donations of information.

If you have a hint, or a useful trick, please consider writing it up and sending it in.



Contact:   S-COM, LLC
PO Box 1546
LaPorte, Colorado, USA 80535-1546
Voice: (970) 416-6505
Fax: (970) 419-3222
E-mail: sales (at) scomcontrollers (dot) com
Contact Bob Schmid directly at scomind (at) aol (dot) com
For reference, the prior address (seen in many old manuals) was Box 1718 in Loveland, Colorado.

Note that the Scom factory still supports all of the 5K, 6K and 7K controllers, including spare parts stock.

The Scom corporate web site has a wealth of information on the Resources page at http://www.scomcontrollers.com/resource.shtml.

One trick that has been done to confuse folks that want to play with your system is to use a courtesy tone that is commonly used by another brand of controller.  The ACC page at this web site has a PDF that describes the factory shipped courtesy beeps.   They are included in the courtesy tones collection page (trust me - the "Nextel Beep" is cute, but becomes real annoying after a while).

The 2.04x version of the firmware for the 7K was developed by Vyex (from the Scom 7K 2.03x firmware) to fully integrate the new Digital Audio board with the 7K controller. A number of very useful features were added at the same time (like an IF-THEN-ELSE construct)...   Support for all 2.04x issues is provided by Vyex, with contact information on their web page.

The Vyex Digital Audio Board  - a replacement for the Scom speech synthesizer board... Bring your 7K up to date!     (offsite link)
Scom Connector pinout  Models 5K, 6K, 7K and 7330
Sample programming for the S-Com repeater controller line  Programmers would call these "code fragments" - just little tricks and treats that others have developed and decided to share.   By Joel Huntley WA1ZYX     (off-site link)
. One method of connection of a repeater controller (the S-COM 7K) to the Micor station   By Bob Hoffman N3CVL     (off-site link)
. Another connection of a repeater controller (an S-COM 7K) to the Micor Unified Chassis Station   By Joel Huntley WA1ZYX     (off-site link)
. Interfacing a GE Mastr II Base Station / Repeater to a S-Com 5K or 7K   (19kb PDF file)   By Bob Schmid WA9FBO of S-Com, LLC.   (Also applies to the 6k with connector pin number changes)   (off-site link)
. Interfacing a Uniden Repeater to a S-Com 5K   (108kb PDF file)   Just change the pin numbers for the 6K or 7K
Recovering the extra User Function Outputs from an S-COM 7K   Eight additonal digital outputs are available from a 7K controller. Here's a schematic of the hardware to do it.   By Andy Zorca WJ9J
Configuring the SCOM 6K to Operate a Link Transceiver   A thorough step-by-step walkthrough, including programming, by Justin Reed NØUJQ   (The technique also applies to the 7k with connector pin number changes)
Programming your Scom 5K, 6K or 7K repeater controller without a radio or a phone line   The pre-7330 S-Com controllers do not have a serial port.   Here's how to get around that.   By Mike Morris WA6ILQ
Analog Audio Delay Module Schematic (ADM)  This is the early analog delay module. Most had two of the pots sealed with glyptal - Don't mess with the sealed pots!
Digital Audio Delay Module Schematic (DADM)   This is the later digital delay module.   Switch setting info is here: http://www.scomcontrollers.com/dadmdoc.html.
Scom 7330 Board Layout   This is worth printing on a color printer and putting inside the case of the controller.

Various Technical Notes on Scom products:

  • Power connectors:
    The 5K, 6K and 7K all used a common coaxial power connector that can be found at any number of suppliers, even Radio Shack.
    The 7330 used a much more sturdy locking connector that is a bit uncommon. It is made by Phoenix Contact company and is their part number 1757019. It's second sourced by Tyco as their part number 796634-2. Digikey sells it as part number 277-1011-ND. If it's in the Mouser catalog I couldn't find it.

  • The 5K, 6K and 7K DADM:
    The connectors on the DADM board and in the controller are not keyed, and depending which end is plugged into the controller (5K, 6K, or 7K) versus the DADM, and depending on whether you chose to have the right angle plug point away from the DADM or towards it, will all be factors in determining which color on the ribbon cable is associated with which signal and pin function. Therefore, you can ignore the wire colors...
    If you look at the DADM's silk screen, between the connector and the board edge you will see "1 2 G + 5". Pin 1 is closest to the centerline of the DADM board, and Pin 5 is not installed (but can be).
    If you accidentally reverse the 4 pin connector, power is applied to the (AC coupled) audio input. You won't damage anything, it just won't work. So just flip over one end.

    1 = Audio Into the DADM
    2 = Audio Out
    G = Ground (negative)
    + = Positive Power
    5 = Audio mute input (optional, see note below on driving it with the receiver unsquelched signal)

  • Another point about the 5K, 6K and 7K DADM:
    Note that there are 5 pins on the schematic, but only 4 on the connector that is soldered to the DADM board. The extra pin is the "erase" line from the digital delay circuitry. It functions as an audio gate function that defaults to the "pass audio" mode. It can be hooked up to the COR line to provide positive audio muting.
    If you present unsquelched audio to the 7K, then Pin 5 should be connected per this table:
    7K Rx1 U27 Pin 11
    7K Rx2 U27 Pin 8
     
    6K Rx1 U15 Pin 4
    6K Rx2 U15 Pin 3
     
    5K Rx1 IC7 Pin 6
    When you assert the COR input whatever is being held in the digital delay is erased. The signal is dipswitch selectable for either high-true or low-true control. If pin 5 is unused then use the "High True" setting.
    Pin 5
    COS Sense
    Switch Setting
    S5 S6
    High True ON OFF
    Low True OFF ON


  • 7330 audio: The audio output circuit of the 7330 is designed to feed almost any transmitter. It's not balanced, it's single-ended. But it is 600 ohms. The output coupling caps are 10 µF, 25vDC, nonpolarized ceramic caps. Their main purpose is to block the 2.5 V bias on the op amp's output but they will also block any DC that might be on the transmitter's mic input. The designers specifically selected nonpolarized caps because the voltage across them can be one way if the transmitter circuit they are driving has no bias voltage, but the other way if the mic input has more than 2.5 V of bias. Almost all Motorola microphone circuits bias the microphone line to +8 to +10vDC to power the preamp inside the microphone.

  • The 7330 has a separate CTCSS encoder on each port, but it can't do Digital CTCSS / DCS / DPL / DCG (pick your appropriate name). The CTCSS output pin can be either the encoder audio output, or a logic output level to control an extenal encoder (it's a three-pin two-position push-on jumper). If you need DPL just set the jumper to the logic output mode and use that to key a Com-Spec DCS-23 board (it's a DPL version of a TS-64) - about $60 (late 2011 price).

  • 7330: The serial ports on the 7330 are common RS232. The old Windows 3.0 and 3.11 had "Terminal.exe" (which I've copied to and used on Windows 98, 2000 and XP), the 95, 98, NT, 2000 and XP all come with "Hyperterminal.exe". It doesn't seem to be installed by default on Vista or Windows 7 but you can copy the binaries from an XP system and they work fine. Just make sure you get all four files:
    1) C:\Program Files\Windows NT\hypertrm.exe
    2) C:\Windows\System32\hypertrm.dll
    3) C:\Windows\Help\hypertrm.chm
    4) C:\Windows\Help\hypertrm.hlp
    (the "Windows NT" section of the path to hypertrm.exe may be different on your system).
    Create a C:\Program Files\HyperTerminal directory in Windows 7 then add the four files mentioned above. Create a shortcut to "C:\Program Files\HyperTerminal\hypertrm.exe" and put it on the desktop, or in the programs menu, or both. Set the file suffix associations to open all "*.ht" files with ""C:\Program Files\HyperTerminal\hypertrm.exe" %1". Note that there are two " characters at the front of the path.
    Opinionated personal comment: I've never liked Hyperterminal and used Terminal.exe on Windows 2000 and XP until I discovered Teraterm (which is now up to version 4.71, released 31 August 2011), however version 3.1.3 is still found out on the web and is perfectly fine. Teraterm can be downloaded for free.
    PuTTY is another option and is also a free download. It is a free (MIT-licensed) Win32 Telnet, Rlogin and SSH client that also happens to do plain serial.


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This web page created 02-Apr-2007 and is © Copyright Mike Morris WA6ILQ.

Information and images published with cooperation and permission of S-COM LLC, All Rights Reserved.

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.