[Gllug] Oyster cards vulnerable?

[John G Walker]

On Thu, 24 Jan 2008 12:18:18 +0000 Ryan Cartwright
<ryan at crimperman.org> wrote:

> Martin A. Brooks wrote:
> > Bruce Richardson wrote:
> >> But there isn't any cash being put on the *card*, is there? 
> > 
> > I was wondering about this myself.  If there's no "cash" on the
> > card, how does Oyster on buses work?   It would require then to be
> > continually connected to the central database in order to process
> > transactions.
> 
> That was why I thought it didn't quite work as centralised as Bruce
> suggests. I always assumed (dangerous I know) that the card contained
> some kind of total itself and this updated the centralised system when
> you next touched it to a connected swipe device (tube station.
> newsagents etc.).
> 
> Certainly if you purchase crdit online the options for updating your
> card on next swipe are generally stations not buses - which implies
> thebuses are not connected. _That_ implies the card has some kind of
> "cash" value stored on it - doesn't it?

If you check your payment history on the TfL website it looks like it
does connect centrally. If you use pay as you go, which I do, it
deducts £4 - the maximum charged for an Oyster journey - from your
credit when you enter the tube system, then credits you with an
appropriate amount when you leave the tube system. You're charged the
standard rate when you get on a bus.

If it didn't connect centrally, then there would be no central record
of your journeys and payments.

If you have automatic top-up enabled, it tops up if necessary on a bus
journey. I've had that happen to me,

-- 
 All the best,
 John
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