Jarle Hammen Knudsen wrote:
On Thu, 29 Oct 2015 00:31:54 +0000 (UTC), Recliner
wrote:

I don't think the gateline has its own clock. The system uses an accurate
clock, presumably synced to an Internet clock. It's noticeable that most
station clocks are accurate to the second these days, just like
radio-controlled watches.

How can the gate write the time of touching in or out to the Oyster
card in a timely manner without having a clock?

It certainly has access to an accurate clock, but whether that's in the
gate itself, periodically corrected, or accessed on-line I don't know.