I was not referring to the calculators, where you have to slot in your bank/ATM card, those are the new ones.
In 1990 when my wife and I setup a subsidiary of a Taiwanese company in Holland, ABN (yes, before the merge with AMRO), had a calculator that could read a kind of flashing bar code from your monitor. You had to hold the calculator against the monitor for a few seconds, then it would display a code you had to type in.
It also gave a numerical stimulus as alternative, in case for some reason, the calculator couldn't read the code from the monitor.
That was twenty years ago, before the Internet became popular and you had to use a 1200 or 2400 baud modem to do your 'telebanking' with a viditel emulator. Probably most of you were still in primary school at that time
Those calculators were somehow tied to a certain number of bank accounts. Some time later, we did telebanking for two other companies, and you really had to use the correct calculator. Else it just didn't work.