A BBC article about 5 things which the article describe as things which might seem obsolete but aren't. Pagers, cheques, music cassette tapes, Tamagotchis, and fax machines:
https://www.bbc.co.uk/news/world-49906336
Re fax machines, from time to time I get asked by banks/building societies for an accountant's reference for one of my clients if they are applying for a mortgage. Strangely enough the banks or building socieites tend to assume that fax machines are the first choice for accountants to send back the completed reference form. I've never had a fax machine myself so I land up by having to copy it and send it through the post.
The firm I used to work for years ago did have a fax machine. That was normal in those days. Back in the 1980s when one of our larger clients was in the process of selling one of its subsidiaries to a FTSE 250 company, before any official announcement was made to the stock exchange out firm was involved in preliminary work. That work had to be done in secret. Although some of the work was done by the specilaist team from London, I and the local partner were the only people in the local office who were involved. There were times where documents needed to be transmitted to the specialist team ASAP. So I had to use the fax machine without anyone else observing me to do that. That's the only time I've used a fax machine.
My time was charged to a business with a fictitious name as we could not use the real business name so as to keep it secret. Turned out that the name wasn't completely fictitious as I got a phone call one day from the audit manager from another office where they had a client with a similar name. I just said it ws just a coincidence.
Our audit files for the last couple of years for the client had to be reviewed by the specialist team in London so the files weren't in our office. So when someone from our tax department wanted to see one of the files I just told him that it was out of the office at the client.
Might seem like undercover work which it was in a way though not as dangerous. It's normal for this to happen whenever a company quoted on the stock exchange is involved in acquring or disposing of a business. That's because until an official statement is made to the Stock Exchange for it to become publicy known, any leak would have a significant effect on the share price which is not a good idea. Or if I had mentioned it to someone and they decided to buy some shares before it became public knowledge they could make money - that's insider trading and doing it is illegal in this country.