On Jun 29, 8:34*am, (Neil Williams)
wrote:
On Sat, 28 Jun 2008 23:42:54 +0100, Paul Corfield

wrote:
Your final option - updated coding on first entry - is correct. All
tickets and smartcards are updated whenever there is a valid transaction
at a ticket vending or validation device.

Except National Rail barriers, surely? *I was fairly sure they were a
read-only technology. *Or is it just understood that they'll probably
end up used on the Tube first anyway, otherwise they'd have probably
been bought from a mainline ticket office instead?

Similarly, does a Tube barrier write to a NR-encoded Travelcard?
Again, I thought it couldn't.

Neil

--
Neil Williams
Put my first name before the at to reply.

I believe both NR and LUL use the same encoding system. NR/LUL
barriers have to write (time and point of entry, etc) to the magstripe
even for ordinary singles, to prevent "passback" (a ticket being
handed back over the barrier for a second passenger to use).

DRH