I think it would be pretty rare for Australian POS machines to handle credit card details. Almost everywhere I only see these systems using a separate terminal with its own network connection to handle the card transaction. Usually there is integration (the POS system tells the terminal the price and to prompt for a card) but I don't think the card data ever touches the POS terminal itself (unlike the way they seem to work in the US).

This is a pretty good system, because the terminals are able to be updated really easily. A lot of cafes and stuff also use iPad POS software (one called 'Vend' is really popular here) and it doesn't have to be certified. This is part of the reason that it took hardly any time for almost everywhere to support contactless six or seven years ago. For example at Myer the POS systems look 15 years old but the attached card terminals are usually only a year or so old.