Also see the separate note below on the use of mobile ("cell") phones.
A "typical maximum" delay of 30 milliseconds is quoted on the web site of NIST in the USA and the same value was quoted by Telstra in Australia in 2003.
Before we proceed, it is important to know, why Microsoft did not build this capability into the Windows operating system, to begin with.
The DS1302 is designed to operate on very low power and retain data and clock information on less than 1μW.The DS1302 has dual power pins, one for primary and another for backup.where telephone signals are "packed" and "unpacked" many times.Therefore it is "conceivable" that delays could be introduced, but these are difficult to quantify.Now that we know why the Windows Taskbar Clock does not display seconds, let us move on.
This is a VERY simple tutorial on how to use the DS1302 Real Time Clock with an Arduino, or Versilino, board. This is my ifrst try at creating an instructable, so I welcome any feedback that anyone has, and I hope you enjoy it. The DS1302 trickle-charge timekeeping chip contains a real-time clock/calendar and 31 bytes of static RAM.When propagated over landlines, any delay within Australia should be "small" for most users.However, all telephone systems world-wide now use transmission technologies involving numerous computer conversion stages, repeaters, etc.On dialling 0900 45-678, the user receives a voice announcement of the time followed by three "pips" of 1000 Hz tone. The announcement and pips are repeated at 10 second intervals to give six time announcements in all, ensuring that the full minute is always included." Spot checks by NZ Section members (some years ago) indicated that there were 'some concerns' over the actual accuracy, but that this time signal is probably within 0.1 second of the correct time.National Measurement Institute (formerly the CSIRO National Measurement Laboratory) - use the 'Capabilities' tab to see their section on Time and Frequency Capabilities To the best of our (April 2006) information, this time signal is stated to be accurate to 1 millisecond (0.001 second) when the time pips enter the public switched telephone network at the source in Melbourne.Only three wires are required to communicate with the clock/RAM: CE, I/O (data line), and SCLK (serial clock).