Telephony is an interesting example because for many many years it had very tight restrictions.
Telephone service providers were monopolies, sometimes government monopolies. There was only one type of telephone you could use, and that was supplied by that same monopoly. It was illegal to attach anything else to the line either directly or indirectly. There were even (outside the US) laws on what you could say when talking on the phone.
Telephone service providers were monopolies, sometimes government monopolies. There was only one type of telephone you could use, and that was supplied by that same monopoly. It was illegal to attach anything else to the line either directly or indirectly. There were even (outside the US) laws on what you could say when talking on the phone.
Here's an article from 1994 about a modem maker who had products that were not officially licensed to connect to the network. https://www.newscientist.com/article/mg14219263-000-technolo...