CASH

Cash is King. Everywhere we went throughout Central Australia, EFTPOS & Credit Card facilities abound. However note that the whole of Uluru, plus other remote communities I would imagine, are kept in touch with the outside world by microwave link. You see a landline phone at the shops, but it is linked back via wireless technology. And this is where you must carry a cash reserve with you.
In Uluru, the microwave link was down for almost 1 day when we were there.
Judging by the pre-made signs that appeared in shop windows & at cash registers, I suspect that this is not an isolated problem.
No mobile phones, no land line phones, no EFTPOS, no Credit Cards, no ATM's. Can get embarrasing if you fill up with petrol, only to discover that Cash is the only form of payment.
A Cash Reserve comes in handy for times like this.