Solo and Maestro cards were embossed but Solo had "electronic use only" printed on the front of the card. Visa Electron cards weren't embossed.
When using the fallback there were different vouchers for different card systems. Visa and MasterCard were on one, Switch on another and Amex had their own as well. This was down to the different merchant numbers for the card systems.
Even though today most EFT terminals accept most cards (I say most, American Express I'm looking at you) when they ask for authorisation online they look at the PAN of the card and work out the card scheme (usually first six digits of the card number) to know which organisation to ask for authorisation. The Merchant Number (or MID/MN) in the background will then auto populate to gain the correct authorisation. Refunds however are usually done offline and are processed in batch when the PDQ polls overnight.
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This is a Eurocard, MasterCard, Interbank and Access imprinter voucher. Visa's were virtually the same.
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This is the American Express version of the voucher which has a different layout to the MasterCard one.
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And this is the style of the imprinter. A lot of retailers still have imprinters but they are more obsolete these days as most cards no longer have the numbers embossed on them. Most retailers will use their PDQ in offline mode until a connection can be re-established. There is also a telephone authorisation line for most card systems which the auth code can be obtained manually when systems go down.