19c2daa00SOllivier Robert<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 29c2daa00SOllivier Robert<html> 39c2daa00SOllivier Robert<head> 49c2daa00SOllivier Robert<meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"> 59c2daa00SOllivier Robert<meta name="GENERATOR" content="Mozilla/4.01 [en] (Win95; I) [Netscape]"> 69c2daa00SOllivier Robert<title>Heath WWV/WWVH Receiver</title> 7ea906c41SOllivier Robert<link href="scripts/style.css" type="text/css" rel="stylesheet"> 89c2daa00SOllivier Robert</head> 99c2daa00SOllivier Robert<body> 109c2daa00SOllivier Robert<h3>Heath WWV/WWVH Receiver</h3> 11*2b15cb3dSCy Schubert<p>Author: David L. Mills (mills@udel.edu)<br> 12*2b15cb3dSCy Schubert Last update: 13*2b15cb3dSCy Schubert <!-- #BeginDate format:En2m -->11-Sep-2010 05:56<!-- #EndDate --> 14*2b15cb3dSCy Schubert UTC</p> 159c2daa00SOllivier Robert<hr> 169c2daa00SOllivier Robert<h4>Synopsis</h4> 179c2daa00SOllivier Robert<p>Address: 127.127.19.<i>u</i><br> 189c2daa00SOllivier Robert Reference ID: <tt>WWV</tt><br> 199c2daa00SOllivier Robert Driver ID: <tt>WWV_HEATH</tt><br> 209c2daa00SOllivier Robert Serial Port: <tt>/dev/heath<i>u</i></tt>; 1200 baud, 8-bits, no parity<br> 219c2daa00SOllivier Robert Features: <tt>tty_clk</tt><br> 229c2daa00SOllivier Robert Requires: <tt>/usr/include/sys/termios.h</tt> header file with modem control</p> 239c2daa00SOllivier Robert<h4>Description</h4> 24*2b15cb3dSCy Schubert<p>This driver supports the Heath GC-1000 Most Accurate Clock, with RS232C Output Accessory. This is a WWV/WWVH receiver somewhat less robust than other supported receivers. It's claimed accuracy is 100 ms when actually synchronized to the broadcast signal, but this doesn't happen even most of the time, due to propagation conditions, ambient noise sources, etc. When not synchronized, the accuracy is at the whim of the internal clock oscillator, which can wander into the sunset without warning. Since the indicated precision is 100 ms, expect a host synchronized only to this thing to wander to and fro, occasionally being rudely stepped when the offset exceeds the default CLOCK_MAX of 128 ms.</p> 259c2daa00SOllivier Robert<p>The internal DIPswitches should be set to operate at 1200 baud in MANUAL mode and the current year. The external DIPswitches should be set to GMT and 24-hour format. It is very important that the year be set correctly in the DIPswitches; otherwise, the day of year will be incorrect after 28 April of a normal or leap year.</p> 269c2daa00SOllivier Robert<p>In MANUAL mode the clock responds to a rising edge of the request to send (RTS) modem control line by sending the timecode. Therefore, it is necessary that the operating system implement the <tt>TIOCMBIC</tt> and <tt>TIOCMBIS</tt> ioctl system calls and <tt>TIOCM_RTS</tt> control bit. Present restrictions require the use of a POSIX-compatible programming interface, although other interfaces may work as well.</p> 279c2daa00SOllivier Robert<p>The clock message consists of 23 ASCII printing characters in the following format:</p> 289c2daa00SOllivier Robert<pre>hh:mm:ss.f dd/mm/yr<cr> 299c2daa00SOllivier Robert 309c2daa00SOllivier Roberthh:mm:ss.f = hours, minutes, seconds 319c2daa00SOllivier Robertf = deciseconds ('?' when out of spec) 329c2daa00SOllivier Robertdd/mm/yr = day, month, year</pre> 339c2daa00SOllivier Robert<p>The alarm condition is indicated by '?', rather than a digit, at A. Note that 0?:??:??.? is displayed before synchronization is first established and hh:mm:ss.? once synchronization is established and then lost again for about a day.</p> 349c2daa00SOllivier Robert<p>A fudge time1 value of .07 s appears to center the clock offset residuals.</p> 359c2daa00SOllivier Robert<h4>Fudge Factors</h4> 369c2daa00SOllivier Robert<dl> 37*2b15cb3dSCy Schubert <dt><tt>time1 <i>time</i></tt></dt> 38*2b15cb3dSCy Schubert <dd>Specifies the time offset calibration factor, in seconds and fraction, with default 0.0.</dd> 39*2b15cb3dSCy Schubert <dt><tt>time2 <i>time</i></tt></dt> 40*2b15cb3dSCy Schubert <dd>Not used by this driver.</dd> 41*2b15cb3dSCy Schubert <dt><tt>stratum <i>number</i></tt></dt> 42*2b15cb3dSCy Schubert <dd>Specifies the driver stratum, in decimal from 0 to 15, with default 0.</dd> 43*2b15cb3dSCy Schubert <dt><tt>refid <i>string</i></tt></dt> 44*2b15cb3dSCy Schubert <dd>Specifies the driver reference identifier, an ASCII string from one to four characters, with default <tt>WWV</tt>.</dd> 45*2b15cb3dSCy Schubert <dt><tt>flag1 0 | 1</tt></dt> 46*2b15cb3dSCy Schubert <dd>Not used by this driver.</dd> 47*2b15cb3dSCy Schubert <dt><tt>flag2 0 | 1</tt></dt> 48*2b15cb3dSCy Schubert <dd>Not used by this driver.</dd> 49*2b15cb3dSCy Schubert <dt><tt>flag3 0 | 1</tt></dt> 50*2b15cb3dSCy Schubert <dd>Not used by this driver.</dd> 51*2b15cb3dSCy Schubert <dt><tt>flag4 0 | 1</tt></dt> 52*2b15cb3dSCy Schubert <dd>Not used by this driver</dd> 539c2daa00SOllivier Robert</dl> 549c2daa00SOllivier RobertAdditional Information 559c2daa00SOllivier Robert<p><a href="../refclock.html">Reference Clock Drivers</a> </p> 569c2daa00SOllivier Robert<hr> 57ea906c41SOllivier Robert<script type="text/javascript" language="javascript" src="scripts/footer.txt"></script> 589c2daa00SOllivier Robert</body> 599c2daa00SOllivier Robert</html> 60