No connectivity for the retailer's device, not for the customer device.
There are also quite a few payment terminals that still do dial-on-demand to get authorisation from the merchant service provider (Chip&PIN/NFC Contactless).
I still see those in the UK especially at independent fuel stations. The additional delay waiting for the terminal to dial and connect sometimes makes me think it has failed - had a few occasions where the line was busy and the terminal redialled several times before it finally made it!
Offline transactions are available in many systems up to certain limits defined by both th card and the terminal. They get reconciled later.
Merchants not having connectivity is a rather small problem in this day and age really, with ubiquitous mobile data connections. (Yes, I am aware someone will be along shortly to tell me they have yet-another-edge case where it doesn't work for them. I don't really care, for the vast majority it is a massively convenient way to conduct business.)
There are also quite a few payment terminals that still do dial-on-demand to get authorisation from the merchant service provider (Chip&PIN/NFC Contactless).
I still see those in the UK especially at independent fuel stations. The additional delay waiting for the terminal to dial and connect sometimes makes me think it has failed - had a few occasions where the line was busy and the terminal redialled several times before it finally made it!