Is this a question? Inventors get patents, not copyrights (although software can be protected by copyright). If you want to pursue this matter, you will need to retain legal counsel. No one will handle a long-shot matter like this on a contingency.
Most lawyers, including myself, offer free consultations and our telephone #'s are on our Avvo profile. You should contact an attorney to discuss this matter.
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If what you have is a copyright rather than a patent, you likely assisted those who developed later versions in creating their own software. A copyright does not protect the method or idea behind the work; it only protects the actual expression of that idea or method. There's a famous case where someone wrote a book about an accounting method and then discovered - much to his chagrin - that he couldn't sue people who began using that method for copyright infringement.
If you had an attorney back in the day, he or she should have helped you to obtain patent protection for your software - that would give you some claim to back royalties for infringing software created before your patent expired. As a non-patent IP person, I can't tell you exactly when that would have been or what might have affected the term. I can tell you, though, that has certainly expired by now.
If you want to pay a litigator to pursue a nuisance suit against these vendors, I have to tell you that they're unlikely to do so at all and almost guaranteed not to unless you're willing to foot rather more than "one $US cent" to cover their fees and costs.
No information you obtain from this answer is legal advice, nor is it intended to be. You should consult an attorney for individualized advice regarding your situation. No attorney-client relationship is formed by my responding to your question.
Copyright only protects direct copying of software code. Not the functionality of software. Two programs, written separately, that perform the same function do not infringe on the respective author's rights.
Circa 1986 software is so difficult to get out of ROMs it would be easier to write your own than reverse engineer a ROM. Your ability to show your software was will be just as difficult.
Even if your claim was valid, you have known about the infringement and done nothing about it since 1986, the statute of limitations has run and your claim would be dismissed as time barred.