In message , at
00:12:30 on Thu, 31 Oct 2013, Neil Williams
remarked:
Would this cause problems?

Yes, because the readers are being modified to accept these as a pseudo
Oyster.

I think presenting two different cards always caused a problem. It's the
Achilles Heel of virtually every RFID card implementation.

On the other hand, my dual "Paywave and Oyster" Barclaycard works fine,
which means perhaps it's got some clever avoidance technology.

--
Roland Perry

On Thu, 31 Oct 2013 09:05:04 +0000
Roland Perry wrote:
In message , at
00:12:30 on Thu, 31 Oct 2013, Neil Williams
remarked:
Would this cause problems?

Yes, because the readers are being modified to accept these as a pseudo
Oyster.

I think presenting two different cards always caused a problem. It's the
Achilles Heel of virtually every RFID card implementation.

On the other hand, my dual "Paywave and Oyster" Barclaycard works fine,
which means perhaps it's got some clever avoidance technology.

It shouldn't be too hard a problem to solve - ethernet has managed to do
collision detection since the 80s. I guess it depends on how smart they
want to make the hardware in the card.

--
Spud

It shouldn't be too hard a problem to solve - ethernet has managed to do
collision detection since the 80s. I guess it depends on how smart they
want to make the hardware in the card.

--
Spud

My Oyster card will not read if I have a PATH Smartlink card next to it.
However, at least four years ago when I last used it, the Smartlink card
will work quite happily on the readers on the PATH turnstiles when next to
an Oyster card, so it can't be too difficult to make it ignore a 'foreign'
card not valid on that system. Of course it's slightly more difficult when
two valid cards, say an Oyster and a VISA debit card can both be seen.

In message , at 23:32:21
on Wed, 6 Nov 2013, Stephen Furley remarked:
My Oyster card will not read if I have a PATH Smartlink card next to
it. However, at least four years ago when I last used it, the Smartlink
card will work quite happily on the readers on the PATH turnstiles when
next to an Oyster card, so it can't be too difficult to make it ignore
a 'foreign' card not valid on that system.

Actually, there's no reason for it to be symmetrical. What if, when
energised, the Smartlink card produces a much stronger signal than an
Oyster so that when used on PATH it swamps the Oyster signal and is
recognised, and on a TfL gate it swamps the Oyster signal and the gate
can't see the Oyster.
--
Roland Perry