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LICENSE: Usage of a LPT-Dongle protected product

Information in this knowledgebase article applies to:

  • All former Keil products, protected with a LPT-Dongle


My old Keil product is protected with a security device/dongle connected to the parallel LPT-Port.

(Microphar: Green=CA166/PK166, Dark Blue=CA51, Red=PK51, Sentinel Pro: product printed on Dongle)

My current PC/Laptop still has a LPT-interface but I will have to exchange the computer some day. New PCs/Laptops ususally don't offer a LPT-Port.


  1. Can I run my Keil product without the dongle?
  2. Is it possible to extend my new PC with a parallel-port extension board (PCI/PCIe)?
  3. Can I update my product to a different licensing solution?
  4. Is a current version of my product compatible with my project?
  5. I have updated my Windows Operating System - is my product still compatible?
  6. Is my former product version still available for download/installation?
  7. How can I compile my application with identical settings and tool versions, but no LPT-Port available?
  8. How can I keep my LPT Dongle protected product supported in the future?


  1. No, the Dongle is mandatory. Without the dongle our tools are limited to the evaluation code size.
  2. Yes, this is possible but it is not guaranteed that all such boards are supported. You can install the Sentinel Protection Installer and see if the dongle is detected. USB to LPT converters usually don't work with this driver.
  3. No, this is not possible. The protection mechanism of old tool versions cannot be updated to USB dongles or node-locked licenses as they are used today. You can also purchase an update and migrate your project to the latest tool versions. Your local distributor can send you a quotation.
  4. No, it won't. Be aware that with each new product version your project can behave differently. It strongly is recommended to compare/test the resulting project from scratch with each new version of your product.
  5. This cannot be guaranteed. For example, a product that was released in 2001 is probably not compatible to an operating system of today.
  6. Most older products were delivered on floppy disks or CD but you can download all versions back to the year 2000 with this link. Note that most CD viewer programs (they start when you insert the Keil CD) are not compatible to Windows 7 and higher. However, you can find the install programs for the 8051, 251 and 166 tools in sub-folders on the CD.
  7. You can't build your application without the dongle.
  8. The only chance you have is to keep an old PC in stock. This PC has to have:
    - an LPT-Port
    - the former Operating System, i.e. Windows XP
    - the Keil product installed.
    Also keep the Dongle stored safely. Losing the Dongle means losing the product. There are no replacement dongles available today.



Last Reviewed: Wednesday, February 20, 2019

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