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Thread: Need a Commander 950 cable.

  1. #1

    Default Need a Commander 950 cable.

    Hi guys & Gals! I'm in desperate need of a Holley 534-140 interface cable. If anyone has one that I can buy, borrow, rent, whatever, I'd be eternally grateful. Any help what-so-ever with this would be greatly appreciated. No Holley has none in stock and no plans to ever have one again. Please feel free to contact me directly. Bill 817-897-6005

  2. #2


    The end should be available. Since Holley no longer makes it, I'd be shocked if they wouldn't offer the pin-out for it. Maybe ask tech and an engineer real nicely for the info. Also, there are a couple complete systems on Ebay for $500-$600 dollars. I have mine in my hand, and if I can get the round connector off without damaging it, I'll be happy to give you the pin-out from end to end. But if I cannot open it without damaging it, I won't be able to help you sir.
    Last edited by Bill C; 06-07-2020 at 05:49 AM.

  3. #3


    Bill C: Thank you for your response. Please don't take any unnecessary risks on my account. I wouldn't want you to risk damaging your cable. With that in mind would you be open to loaning or renting yours to me for a short while in order that I can access this unit and program it? I can assure you nothing adverse will happen to your cable. I can provide to you my FedEx account number for safe shipping. I can also provide you multiple trade references as well. Thanks, Bill Ancona

  4. #4


    Guy said $350 plus shipping for the whole system, even comes with laptop:
    Last edited by Bill C; 06-10-2020 at 06:27 AM.

  5. #5


    Bill, can we talk on the phone sometime?

  6. #6


    Note I'm not any Commander 950 expert, but if you look at the Tuning Manual on for it, where they show the wiring diagrams near the end. There is some info on the pin numbers and colors for that round laptop communications connector.

    I have no idea what the ModA and ModB pins are for on the ECU (+5V?) so please do your own research/diligence on any of this, I'm just putting it out there as a possibility. I wonder if you could simply pick up a simple RS232 USB or DB9 pigtail to wire up for the TxD, RxD, etc. and have it work?

    Hope this helps in some way, or someone else who is more familiar can chime in to help get you sorted. Best regards, Frank

    HP EFI V4, 388cid Stealth Ram, 1000 CFM 58mm throttle body, Holley Dual Sync Distributor. LS Coil Near Plug, 1 bar MAP, 48 lb/hr Holley EFI injectors, 43 psi

  7. #7


    The old C950 used a serial port connection, it was not USB compliant. You'd have to use a DB9 serial port to USB adapter. Plugging directly into a USB could cause problems.

    Quote Originally Posted by Kwik One View Post
    Bill, can we talk on the phone sometime?
    Sure, message me through this board and I can give you my cell number, although Sundays are best for me. I work odd hours.

  8. #8

    Default Making contact possible.

    Bill C, I'm not sure how to message you privately, so hopefully you see this. Please text me or feel free to call me at your convenience. Sundays are fine for me as well. If you miss me, please leave a number and call back time, or like I say text that information. Thanks,
    Bill Ancona

  9. #9


    I sent you a message with my cell number.

  10. #10


    I had a few minutes to play with this last night. Only three wires of the DB9 serial port end are being utilized. I'll map it and post the info ASAP. Hang in there buddy.

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