Date: Sun, 10 Mar 2013 17:05:12 +0000
From: Joe Loughry <
[email protected]>
Subject: Radio controlled clocks misinterpret daylight saving time warning bit
Some radio synchronised clocks in USA unexpectedly switched to Daylight
Saving Time (DST) yesterday hours ahead of schedule. According to the Time
and Frequency Division of the National Institute of Standards and Technology
(NIST), which operates radio station WWVB in Boulder, Colorado, the last two
significant bits in the time code give a warning that DST changes tomorrow
and the current state of DST (standard time or daylight saving time). Some
clocks changed to DST when the warning bit appeared.
Some older radio-controlled clocks may adjust for Daylight Saving Time early
Joe Loughry, Doctoral Student in the Department of Computer Science
St Cross College, Oxford