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<title>Ultralink Clock</title>
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<h3>Ultralink Clock</h3>

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<h4>Synopsis</h4>
Address: 127.127.34.<i>u</i><br>
Reference ID: <TT>WWVB</TT><br>
Driver ID: <tt>ULINK</tt><br>
Serial Port: <tt>/dev/wwvb<i>u</i></tt>; 9600 bps, 8-bits,
no parity<br>
<br>Features: <tt>(none)</tt>
<h4>Description</h4>
This driver supports the Ultralink Model 320 RS-232 powered WWVB receiver.  PDF specs available on <a href="http://www.ulio.com">www.ulio.com</a>.
This driver also supports the Model 330,331,332 decoders in both polled or continous time code mode.  Leap second and quality are supported.

<P>Most of this code is originally from refclock_wwvb.c with thanks.  Any mistakes are mine.  Any improvements are welcome.
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<pre>
  The Model 320 timecode format is:
 
   <cr><lf>SQRYYYYDDD+HH:MM:SS.mmLT<cr>
 
  where:
 
  S = 'S' -- sync'd in last hour, '0'-'9' - hours x 10 since last update, else '?'
  Q = Number of correlating time-frames, from 0 to 5
  R = 'R' -- reception in progress, 'N' -- Noisy reception, ' ' -- standby mode
  YYYY = year from 1990 to 2089
  DDD = current day from 1 to 366
  + = '+' if current year is a leap year, else ' '
  HH = UTC hour 0 to 23
  MM = Minutes of current hour from 0 to 59
  SS = Seconds of current minute from 0 to 59
  mm = 10's milliseconds of the current second from 00 to 99
  L  = Leap second pending at end of month -- 'I' = inset, 'D'=delete
  T  = DST <-> STD transition indicators
 
  Note that this driver does not do anything with the T flag.
 
  The M320 also has a 'U' command which returns UT1 correction information.
  It is not used in this driver.
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<pre>
  The Model 33x timecode format is:

    S9+D 00 YYYY+DDDUTCS HH:MM:SSl+5

  Where:

  S =    sync indicator S insync N not in sync
         the sync flag is WWVB decoder sync
         nothing to do with time being correct
  9+ =   signal level 0 thru 9+ If over 9 indicated as 9+
  D  =   data bit ( fun to watch but useless ;-)
  space
  00 =   hours since last GOOD WWVB frame sync
  space
  YYYY = current year
  +  =   leap year indicator
  DDD =  day of year
  UTC =  timezone (always UTC)
  S  =   daylight savings indicator
  space
  HH  =  hours
  :  =   This is the REAL in sync indicator (: = insync)
  MM  =  minutes
  :  =   : = in sync ? = NOT in sync
  SS  =  seconds
  L  =   leap second flag
  +5 =   UT1 correction (sign + digit ))
 
  This driver ignores UT1 correction,DST indicator,Leap year
  and signal level.

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<pre>

Fudge factors
	 flag1  polling enable (1=poll 0=no poll) 


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    <address><a href="mailto:dstrout@linuxfoundary.com">mail</a></address>
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Last modified: Tue Sep 14 05:53:08 EDT 1999
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