I have built an app on top of an existing ancient software application. That ancient application exists of two parts; a software application and some actual hardware that provides specific sensor data that is shown inside that application. That data is provided over RS232 and is just raw and freely available.

I just put a splitter cable between the sensor and the existing application. And from there on I use that data to be used in my own app.

The customers of this ancient software application buy their software and hardware sensors. All I do is provide these same customers an option to view the same data but via an app, for a small monthly fee ofcourse.

The creator of the ancient software application caught wind of this and now says: hey, this is forbidden, you can't do this and you need to stop.

So the question is; the data is available. I don't touch their software, I simply bypass it. Can they actually make me stop? Do they have any say in this?

  • If the data is freely available why don't you simply buy hardware sensors separately? And you say the data is freely available, but also say is it "their" data, which implies it is proprietary, and there are probably terms and conditions associated with purchase of their product. And which seemingly contradicts "freely available"... Commented Feb 15 at 23:29
  • 1
    This sounds like something where you need a lawyer in your jurisdiction. If you think that asking this on the web is a good idea, that's a clear sign that you need expert legal advice.
    – o.m.
    Commented Feb 16 at 6:45
  • @ o.m. I was going to ask a lawyer anyway but just wanted to get a feel. @MichaelHall The data comes from sensors they installed. Buying these hardware sensors gets me into the 'hardware department' of the business; I don't like that. I am a software developer so I like to keep it to just the app instead of installing hardware senors I have no knowledge about.
    – gerb0n
    Commented Feb 16 at 7:44
  • How is something "freely available", that you have to buy from a specific vendor, signing their contracts? Also, do you market your product using their company name? Do you say "This allows you a companion app for $AncientSoft's Application"?
    – nvoigt
    Commented Feb 16 at 9:27
  • 1
    In the Netherlands, reverse engineering for purposes of software interoperability (IE allowing so that your software can interact with someone elses software/hardware) is legal. And it is actually against the law to have a ToS that prevents it... Not a lawyer.
    – Questor
    Commented Feb 16 at 21:00

1 Answer 1


You can definitely legally never use the manufacturer's software. But you need to consider:

  • Whether, if you have used their software in the past, you agreed to a contract where you promised not to bypass it, or to develop tools to bypass it.
  • Whether bypassing the software would void your license to use that software concurrently or in the future.
  • Whether not bypassing the software was a condition of the purchase agreement for the hardware.
  • Whether the original company is actually just lending you the hardware, on the condition you only talk to it with their software, per some agreement they waved about when installing it.
  • Whether the original company will refuse to provide support to or do business with anyone who they find out uses your product.

So what you want to do is either perfectly fine, or not allowed because you "agreed" not to do it, but it's impossible to tell which without an enumeration of all the agreements in play.

  • I do not think the OP wants to use the other company's software. Commented Feb 17 at 23:48
  • @GeorgeWhite I think OP said they had a splitter cable connecting the device, the original software, and their better software all together.
    – interfect
    Commented Feb 18 at 2:37

Not the answer you're looking for? Browse other questions tagged .