What time is it? [Telecom]

I woke up this morning to find that my "automatic" alarm clock had reset itself to one hour before the real time. In like manner, my VCR was also an hour behind the times.

My alarm clock is the kind that sets the time automagically when you plug it in, and my VCR is supposed to get its time from the Vertical Interval Reference signal sent by PBS stations.

I am confused: I know that Daylight Savings Time doesn't end until next Sunday, but neither my "self setting" clock nor my VCR seem to have gotten the word.

What happened?

Bill Horne Temporary Moderator

Reply to
Telecom digest moderator
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This is probably courtesy of The Best Congress Money Can Buy [tm].

For some stupid set of reasons or another, that defied all logic to anyone who actually gave it a thought or two, they passed, and President Bush signed, "Energy Policy Act of 2005".

To quote from wiki's writeup: " Clocks were set back one hour on the first Sunday in November (November 4, 2007), rather than on the last Sunday of October (October 28, 2007).

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(Note that there were plenty, make that PLENTY, of other nooks and crannies in that act, few of which were common public knowledge. That wiki article has a good summary)

Reply to
danny burstein

Sounds like your local PBS station forgot something. My VCR is fine.

***** Moderator's Note *****

Actually, it sounds like my VCR is programmed to set back on the _old_ date, instead of the "improved" date, which is next week. What was it Mark Twain said about being an idiot and being a Congressman?

Bill Horne Temporary Moderator

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Reply to
Steven Lichter

Your VCR most likely doesn't have any way to upgrade its firmware to the new rules.

Most time-sync technologies provide a time reference in UTC, and expect the receiving device to apply any timezone differences -- including the Daylight Saving Time offset when appropriate.

The changes to U.S. DST made for a busy cycle of patching and testing for IT folks, but there was nothing to be done for a vast array of devices with embedded WWV radio clocks, VBI receivers in TV equipment, etc. that had no provisions for firmware upgrades or new timezone tables.

Reply to
Rob Levandowski

My understanding:

The current rules for the period in which Daylight Saving Time is observed went into effect in 2007.

The radio time signal includes a bit that flags whether DST is in effect. My Chinese-made clock sets itself via the radio time signal. It was designed before the law changed, yet correctly correctly observed the start of DST in 2007. It has a switch to display Standard Time all year 'round for parts of the country that don't observe DST.

I don't understand what happens on transition days since DST starts and ends at 2 am local time and there's only one radio time signal.

The television time signal doesn't include a DST flag so the rules for when DST is to be observed would be hard coded into your machine.

Reply to
Adam H. Kerman

Some years ago I bought an RCA TV and it had a TV Guide program that would update, well a few years ago it just stopped working, it appears they no longer support it. I have sat so I don't really care now.

Reply to
Steven Lichter

While VCRs and some other equipment may have firmware encoded DST information, WWVB actually transmits a DST bit which a radio clock can either honor or ignore depending on a switch setting. The day the clocks change is not encoded into them, but is transmitted from the source.

Bill Ranck Blacksburg, Va.

Reply to
ranck

The _rules_ changed. Your equipment was bought *before* the rules changed. The programming *built*into* the device operates by the 'old' rules.

Either "live with it", or buy new gear.

Reply to
Robert Bonomi

A third option is to write your congressman and complain about ludicrous and unnecessary rules changes which benefit no one but the people paid to draft new rules.

--scott

Reply to
Scott Dorsey

WWVB transmits GMT. Your clock also has a setting for time zone, so it knows you are in Eastern, or Central, or Mountain, etc. That gives it the offset from GMT and makes the change at the appropriate time after the DST bit is set.

Bill Ranck Blacksburg, Va.

Reply to
ranck

Note - in the good old USA.

Most of the rest of the world manages to ignore this improvement in gratuituous changes to standards......

having said that, different bits of Europe change to summer time on different days (or at least used to) which is always fun if you use planes / trains across frontiers at just the right time.

Reply to
Stephen

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